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FAQs on the Molly Health/Disease 7

Related Articles: Mollies, & Poeciliids: Guppies, Platies, Swordtails, Mollies by Neale Monks, Livebearing Fishes by Bob Fenner,

FAQs on Molly Disease: Molly Disease 1, Molly Disease 2, Molly Disease 3, Molly Disease 4, Molly Disease 5, Molly Health 6, Molly Health 7, Molly Health 8, Molly Health ,
FAQs on Molly Disease by Category: Nutritional (e.g. HLLE), Social, Infectious (Virus, Bacterial, Fungal), Parasitic (Ich, Velvet...), Genetic, Treatments
FAQs on Molly Reproduction/Breeding
Molly Reproduction 1, Molly Reproduction 2, Molly Reproduction 3,

Sick Molly?, 11/26/10
My Molly is black with white specs (Dalmatian Molly?) and I have had him for about 2 weeks now and have introduced two new fish, another Molly and a Pleco!
<Hope this is a big tank or a smaller species of Pleco. Also note that mollies generally do much better in brackish conditions than fresh.>
Even before introducing these two new fish my black Molly has been constantly sitting on the bottom of the tank, barely moving. When he does move it's only when I feed him and he doesn't go up for food every time.
When he does go up for food it seems like he is having trouble staying up at the surface. I have actually watched him sink to the bottom and just give up. Also, I have found that when he is sitting at the bottom of the tank his head starts to float upwards to the point where he is "standing" on his tail and his anal fins are spread right out. He literally sits on the bottom of the tank for hours, I have to keep checking to see if he is still alive. However, every once in a while he does go for a little swim and then heads straight to the bottom again. What is wrong with my Molly?
Is he sick or just tired? Cause I have heard that mollies can get exhausted.
Thank you for your time,
<Water conditions are the most likely cause of your issues. What are your ammonia, nitrate, nitrite, and pH readings? See here for more,
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm >

Mollies, reading 11/15/10
Good Afternoon,
I've been searching and can't find the correct diagnosis and answer.....
My black female molly is swimming on her side but not completely, she eats, is still aggressive, her spine is still straight, she's normal just on her side.......is she sick or fixing to have her fry?
<?... need more info...>
I have 13 other molly in the tank w/her and all are fine....its just her.
Thanks in advance!
<Read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above. Bob Fenner>

mollies dying 9/22/10
<Hello Ruth>
I've looked and read and added new keywords but I can't find an answer that fits, so I'm sorry to bother you but here it is...
55 gallon tank
all water readings within parameters (ammonia, nitrate 0, nitrite 15)
<Mmm, the last two turned about... 15 ppm of nitrAte likely>
Two weeks ago the male orange molly died - he seemed to get darker in the preceding 2-3 days, but nothing else noticeable. In the last two days I've lost two female mollies, both pregnant. One was pregnant for at least 5 weeks and just kept growing - she slowed down over 3 days, at one stage sitting on the bottom the tank, but her appetite appeared normal. Behaviour and swimming pattern normal. She died without visible warning/symptoms of anything, overnight.
<Mmm, what particular species of Mollienesia is/are this/these? What pH, hardness... do you utilize (sea) salt in their system? Turns out, though Mollies are popular aquarium fishes, they do very often perish in short order>
The other died tonight. When I got up this morning she had a whitish film on her nose - I netted her very gently for a closer look and after initial thrashing she went limp in the net (I thought I'd killed her for a second), however by tonight the film had spread over one side of her face and eye, and her mouth was open (not gasping). I isolated her in the same water, but she died.
Both of them, on death, had open mouths and what appeared to be swelling (as thought their mouths had been forced open by the swelling) and what appeared to be black colouration inside their mouths.
What a XXX way to die is all I can think...what the hell am I doing wrong?
<Can't tell from what you've related... but almost invariably these species die from related environmental issues>
Poor buggers...
Other fish; 1 pregnant guppy (male died 10 days ago without any similarities, and without warning), 1 rainbow shark, 1 juvenile female molly, are fine. I do have snails breeding out of control over the last 2 weeks - any connection do you think?
Thanks for any information/advice you may have on this - I feel so bloody responsible and ignorance is never a good excuse. Damn.
Ruth Perry
<Do please read Neale's work here:
and the linked FAQs files are their Health/Disease, Systems above. Bob Fenner>

shy Gourami and vertical molly 8/22/10
I have a 72 gallon fresh water community tank. Tank is fully cycled and established. Regular weekly maintenance (water change, gravel siphon, glass cleaned with cleaning tool and all water conditions monitored and within acceptable parameters.
<Meaning what, precisely? Mollies require very different water conditions to South American tetras, and it's hard to see how you can have "acceptable" water for both in one aquarium. Even if you don't maintain Mollies in brackish water -- and to be fair, some people manage to keep them in freshwater just fine -- they still need warm, hard, basic water.
Danios require cooler water, and Tetras softer water.>
No live plants, though several fake plants and multiple hiding spots for the varied fish There are 3 gouramis in the tanks (along with other species - all community/peaceful -Danios/tetras/mollies/2 clown loaches/Cory/Pleco).
<See above.>
Of the 3 gouramis, one is acting what I define as strange. During the "daytime' or when daytime light is on the tank, it will "hide" in one corner of the tank. However if I run the "blue" light that I have for night time viewing, this Gourami becomes active and swims throughout the whole tank and socializes with the other fish. During the day or with day lights on this
Gourami will run from the other gouramis as if being chased, however under the blue lights shows no such sign of submission and chases the others as much as anything else. No obvious physical issues, and seems to be eating regular.
<I do think this is aggression. Assuming this is Trichogaster trichopterus,
the males -- which have longer dorsal fins -- are famously aggressive towards one another. Adding more females might dilute things, and keeping just two males within a group of three is bound to cause problems because one male can always bully the other. Try keeping at least equal number of females to males, and either one male or at least three.>
Have also noticed that a silver molly (relatively new tank member - 2 weeks) swims around in a "vertical" posture, nose up/tail down - almost like a rocket ship taking off.
<This is likely "the Shimmies", a neurological issue related to poor environmental conditions. Mollies need 15+ degrees dH, pH 7.5-8.5, and a temperature between 25-30 degrees C. Danios won't enjoy water that warm, and neither will Corydoras or tetras such as Neons; all of these are better kept at 22-24 C. Obviously, most freshwater fish won't tolerate brackish water, but even the hard water Mollies need will significantly shorten the life of the more sensitive South American tetras such as Neons and Cardinals.>
It is capable of swimming horizontally, and will do so for a while and then go vertical even though it is swimming along a horizontal plane. My local fish supplier says that this is a common trait of this species, but I have never seen so before. Again no obvious physical or eating issues. Any thoughts/advice would be appreciated.
<It's possible the Molly has constipation or is simply genetically deformed, especially if the thing is inbred or one of those ghastly Balloon Mollies. But if the fins are clamped, or the fish rocks when treading water, then Shimmies is very likely the problem. Constipation can be cured using high-fibre foods such as peas and spinach, together with Epsom salt if needs be:
Genetic problems aren't fixable, and the Shimmies goes away usually if the Molly is given good conditions:
<Cheers, Neale.>
Re: shy Gourami and vertical molly
Thank you for your response,
<Glad to help.>
I will try provide the further information you require.
Maintenance: weekly water changes, approx 30%-40%, use floating glass cleaner to clean glass and gravel syphon to suction gravel. Fluval 404 canister filter Water conditions: Ph maintained at 7.0 as much as possible, checked twice a
week. Nitrates checked weekly usually around 5 (lowest number on scale).
Ammonia tested weekly usually 0-0.25 (keep a hang in tank monitor in the tank to visually check daily - unsure how accurate these are).
<Very inaccurate. Do have the water tested with a liquid test kit; if not zero, then you have a problem with water quality.>
Also check Phosphates and usually 0-0.25. Haven't tested the water hardness in a while, but believe it to be hard (will get test kit to test). Usually test water 2-3 days after water change to give numbers a chance to balance.
Is this the proper type schedule. Anything specific I should be checking as well?
<What you're doing sounds fine.>
Sorry not sure what you refer to as "basic" water?
<Basic is the opposite of acidic; i.e., pH 7 upwards. At school you might have learned "alkaline" for this, but actually alkaline means something quite specific, though closely related.>
Usually attempt to maintain a water temp of 76F (24C)
Food: TetraAlgae vegetable enhanced chips. Nutrafin Max sinking pellets (for bottom feeders (loaches) bloodworms (every 10 days or so as a treat
<All sounds fine.>
Tank inhabitants:
1 Bristlenose Pleco (2yrs in tank )
2 Clown loaches (2 years in tank)
6 Zebra Danios (3 months to 1.5 years)
6 Cardinal Tetras (1 year)
1 Juli Cory (1.5 years old)
2 black and 2 silver mollies (1 silver molly 1 year, other 3 - 2 weeks in tank). They are not balloon mollies.
3 Gouramis (1 moonlight and 2 sunburst - the moonlight Gourami is no problem (except chases the air bubbles), the solitary Gourami is one of the sunburst).
<Right, the Sunburst Gourami is, I believe, a variety of Colisa lalia, a very risky species. Highly prone to Mycobacteria infections as well as a viral infection all its own called Dwarf Gourami Iridovirus. Not a species I ever recommend. Sad, because it's a nice fish. But inbreeding and intensive farming has completely ruined this species.>
Between my LFS and the web, I thought I had done my homework regarding water/environment compatibility within the tank (www.peteducation.com/article.cfm?c=16+1911+1957&aid=2572
- was one article that led me to believe mollies and gouramis were compatible) - though I am sure there are others to indicate non-compatibility. However your information indicates the mollies do not fit within this grouping and I am willing to accept your analysis.
<It's not that you can't keep Mollies with Gouramis; it's that you can't *always* keep Mollies with Gouramis. About 50% of the time Mollies just don't do well in freshwater communities. Some folks write that off, and say if the Mollies aren't happy, take them out and try something else. Or alternatively, keep medicating as often as required. Or worse, treat them
as disposable fish, and when they're sick, euthanise them and buy some more. My argument is towards providing such conditions for Mollies that you have as near to 100% chance of success as possible. So certainly that means the water should be hard and basic (alkaline) but it also means keeping your options open so you can add some marine salt mix. Some tropical fish don't mind a little marine salt mix, and will thrive under those conditions. Most other livebearers for example, as well as things like Australian Rainbowfish, many Killifish and Cichlids, and certain catfish such as Brown Hoplos. But on the other hand, there are fish that dislike salt immensely, including most tetras, barbs and gouramis.>
You seem to indicate that the best move is to remove the mollies from the mix and I will probably go that route.
<Does tend to be my recommendation. Mollies are fine fish, but you need to work around them.>
In the interim, will the Epsom salt have any effect on the other fish in the tank/ should Epsom salt be a regular addition to the tank?
<Epsom salt won't have any negative effects on the other fish. It IS NOT an substitute for marine salt mix, but rather a laxative that helps relieve constipation. It also raises general hardness, but that's something different to salinity.>
If there are any other compatibility issues I would appreciate further direction.
<I think we've covered everything!>
Not sure of the sex of the gouramis - I was not there when purchased - will attempt to determine
<Your Colisa lalia are males if colourful, females if plain silver.>
I do not use any aquarium salt, should I?
<Some folk do add "teaspoon per 5 gallon" amounts to community tanks but there's not much reason to. Do read here:
Also have not had much luck with live plants (mollies ate everything I put in there - which I understand they do)
<Not normally. They much prefer algae, which is their natural diet. But certain soft plants may be nibbled on. Try Indian Fern, a species that is clearly good to eat but also fast-growing, so tends to hold its own.>
plus most of the information I was given seemed to indicate the conditions for healthy plants were not compatible with
my fish. How important are live plants?
<They aren't crucial at all. Plants provide shade, but you can do that with plastic or silk plants. Plants remove nitrate of course if growing fast, but water changes will do that too. Fast-growing plants do prevent algae though, and that's difficult to do otherwise, so again, clumps of floating Indian Fern can make a huge difference if you're constantly wiping algae from the glass.>
Bubble wall - I am not a huge fan of it esthetically, however if its good for the fish I'll keep it. Recommendations?
<If you don't like it, don't use it! Contrary to popular misconception, bubbles don't "force" oxygen into the water. What bubbles do is move the water from the bottom of the tank to the top. If you do that using a good strong filter, then bubbles are redundant. Switch the thing off, and see what happens. If the fish seem just as perky as before, then leave the
bubble wall off, or perhaps switch it on during hot spells when you worry the water might be holding less oxygen than it should -- you can tell because the fish become sluggish or hang about close to the top of the tank. Do note that Mollies and Gouramis do this naturally, Mollies to breath the air/water mix, and Gouramis to breath air directly, so just because they're at the top of the tank doesn't mean something is wrong.>
Finally, if there are no further compatibility issues, are there any fish species that you would recommend to me.
<I think you have a fine mix of fish! You should add some more Julii Corydoras because they are sociable. Clown Loaches get very big, and also eat soft plants, so I'd tend to recommend Yo-yo Loaches or Dwarf Chain Loaches over Clown Loaches. If you want a livebearer, I suspect either Platies or Swordtails will be better in this tank, depending on its size and how strong the water current is, Swordtails being bigger, more active, more aggressive, and preferring strong water currents. Failing that, Wrestling Halfbeaks are weird and lively, if a bit more difficult to keep.>
<Cheers, Neale.>

Dead Sailfin Molly 8/21/10
Dear WWM Crew, thank You very much again for your sincere and prompt help in the past.
<Glad to help.>
Last night one of my Sailfin mollies died. Actually today morning it died in the hospital tank where I had put it with Methylene blue and tetracycline. It has a injury mark on head.
<I see.>
I would seek to kind help to find out if its a physical injury or an infection.
<Impossible to say.>
Please see the photo attached. Another confusion I would like to ask that we generally read that 20% water change every week is sufficient. However is this also hold true for small tank [ say 6 Gal ] and for new tanks being established?
<You can't keep Mollies in 6 gallons, and you can't keep Mollies in freshwater tanks that aren't fully cycled (i.e., at least three months old).>
If not, how much water change should be done in these two cases? Thank You in Advance
<Do please read about these fish:
All the medications in the world won't help if the living conditions are wrong. Cheers, Neale.>

Lots of Molly questions, sys. hlth., reading 7/22/10
Hi everyone!
I've read so many articles from your wonderful website that my eyes are crossing! =) Reading through the FAQs has been incredibly helpful over the past couple months in helping me properly set up and maintain my 7 tanks (for the time being...this is a very addictive hobby to say the least).
<Good to know. Do make sure to read here:
Most problems with mollies come down to the wrong environmental conditions. Specifically, too small a tank, too soft water, too cool a temperature, and often, lack of marine salt mix to raise the pH, hardness and salinity.>
The tank I have a question about is my 10 gallon Molly tank.
<No such beast as a "10 gallon Molly tank". These fish need 20 gallons, minimum, for the Shortfin varieties, and 30 gallons upwards for Sailfin varieties.>
I started off with 2 female and 1 male (and 3 Mystery Snails to help with any uneaten food, not that the Mollies leave much behind).
<Apple/Mystery snails are not compatible with Mollies. Oddly, they do occur in the wild together. But the snails need cooler, less saline conditions so it's difficult to provide good conditions for both.>
The male is a silver Sailfin, one female is a black 'regular', and the other female is a Dalmatian Lyretail (who I was told was really pregnant when I got her, but now I think she may be some type of a balloon belly but I'm not positive). The male (White Lightning) showed absolutely no interest in the Dalmatian female (Starry) and was constantly chasing the black female (Stormy), showing off his Sailfin and swimming circles around her only allowing her a few minutes of peace at meal times and when she would lose him for a few minutes hiding amongst the plants and decorations.
<Inevitable in a tank this small. Stress will be the result.>

About 3 days ago I noticed Starry's behavior changing. She swims around some, she comes up for food or when I'm sitting in front of the tank talking to them, but mostly she stays near the bottom in the middle of the tank slightly above the gravel just wiggling back and forth (kind of hovering in one spot).
<Could be stress-induced, or water quality, or water chemistry.>
Occasionally she'll swim around the tank (looking for food I think), but usually she just stays in her 'spot'.
<Do learn to recognise "the Shimmies", a disease where Mollies seem to tread water. In serious cases they adopt odd swimming angles, rock from side to side, and eventually die. It's neurological, and caused by environmental stress.>
I've also noticed her kind of spasming a few times, not very often but maybe once a day for the past 3 days I've seen it. She'll be hovering near the bottom and all of a sudden she turns almost sideways to the left until her side brushes against the gravel and then she flips back upright immediately. It kind of reminds me of when a cat is about to flop on it's side to lay down. She still eats normally (always searching for food) and doesn't have anything odd on her body, no fungus or Ick-like spots, her fins are all in good condition, her eyes are clear, her poo is normal looking medium brown color like the others.
I did some research on your site, and decided I should get 2 more females to keep White Lightning company (and give poor Stormy a break), and that I needed to add salt to the water to hopefully help with Starry's shimmying issues.
<I'm surprised that in your research you missed the need for specific environmental conditions. If fish aren't unhealthy, adding more of them rarely improves things. Sure, adding extra Neons to a school of them will make them less nervous. But if the fish are visibly sick, then the first order of business is environment. Mollies can't be kept in 10 gallons, period.>
Off to PetSmart I went and purchased Moonbeam (silver 'regular' female) and Estrella (Dalmatian 'regular' female). I also purchased a box of API Aquarium Salt and a Tetra Whisper 2-10 gallon power filter to add to the Aqua Clear 10-30 gallon filter I already had to help with the extra fish.
<Again, you're missing the key things. Aquarium salt isn't what you need, marine salt mix is. There's a vast difference between them. Marine salt mix doesn't just add sodium chloride but also raises pH and provides the carbonate hardness that inhibits pH changes between water changes. It's like comparing water and wine -- they're both wet, but they're very different things. Adding extra filters is always a plus, but if the tank is too small, that's like sticking an extra engine onto a two-seat car -- it'll still only carry two people.>
Since it was tank cleaning day anyway I already had water sitting out to age overnight with the Tetra Aquasafe in it. I emptied out 3 gallons of water with the gravel cleaner thingie, rinsed off the filter media from the Aqua Clear in the old tank water and added the new water and the new filter. I added 2 tablespoons of the aquarium salt mixed with tank water to the aquarium (per the instructions on the box).
<The manufacturers of aquarium salt are being disingenuous, because they know that the only people who buy salt are inexperienced beginners. It's a shame, but there you are. For Mollies, you're aiming for a slight salinity, around SG 1.002-1.003, about 4-6 grammes per litre, or 0.6-0.8 oz per US gallon. Using spoons is pretty hopeless because salt packs down and it also absorbs moisture from the air, so the amount of salt per spoonful varies.>
Then I added Moonbeam and Estrella to the tank (they had been floated in the tank for 15 minutes and then placed in a 1 gallon Kritter Keeper with 1/2 their bag water and 1/2 tank water while the cleaning was going on). They both stayed near the bottom in a corner for about 10 minutes and then slowly started exploring. But Moonbeam seems to be acting like Starry, I usually find her hiding in a corner of the tank just wiggling (no flopping though and she does swim around more than Starry does).
Estrella likes to run interference for Stormy, trying to distract White Lightning when he's chasing Stormy around the tank.
<You're applying human hopes to animal behaviour. None of your Mollies are acting in the way you're describing. Individual females couldn't give a rip about other females, and don't do anything to "distract" males.>
But White Lightning still doesn't show much interest in anyone else, he'll 'sniff' around the other 3 briefly but as soon as he catches sight of Stormy he's off to chasing her again. He'll swim up underneath the others and check out their anal vent area but he never flings his Sailfin up like he does with Stormy and he doesn't chase any of the others or seem interested in them at all. I'm pretty sure Stormy is pregnant now, Starry may be, and I'm pretty positive Moonbeam and Estrella aren't (at least not yet).
<They are.>
Now for the questions (finally!): What could be wrong with Starry?
<Nothing. What's wrong is you put these Mollies in a tank far too small for them. The result is aggression and stress. Completely predictable.>

Should I quarantine her from the other fish or is this normal Molly behavior?
Is it normal for a male to only show interest in 1 female out of 4?
<Sure. He'll probably mate with them all, but his attention will be most focused on whichever ones exhibit what he sees as the best genes.>
Is the aquarium salt enough for the Mollies
<No, it's rubbish. Or rather, it's specifically for treating Whitespot and the like.>
or do I need to get something different to make the water brackish?
<Yes, marine aquarium salt mix.>
PetSmart told me the aquarium salt was fine
but I think I read on here that Marine Salt should be used.
ask the clerk at PetSmart about how sodium chloride raises pH and carbonate hardness. Then ask him what carbonate hardness is for. If he can't answer those correctly he should stick to selling canned dog food.>
Or do I need to add more aquarium salt? (I've read anywhere from 1 tablespoon per gallon to 1 tablespoon per 5 gallons.)
<Not by spoons, by weight, though conveniently 6 grammes of marine salt mix should be about 1 level teaspoon, so about one-half to three-quarters of a level teaspoon per litre should be just about right. Since Mollies don't need a specific salinity, any slight variation won't do any harm so long as you don't add so much the filter bacteria and/or plants get stressed. Mollies themselves are happy in fully marine conditions, so salinity isn't an issue for them.>
Is the aquarium salt dangerous to the Mystery Snails?
<Yes, it kills them.>

They seem to be acting normal since I added it, but I don't want to hurt them either. Is it ok to keep 5 Mollies and 3 Mystery Snails in a 10 gallon tank or do they need more space?
<You need a 30 gallon tank, minimum. Don't have that kind of space? Don't keep Mollies. There are lots of alternatives:
All of the Mollies are 1 1/2 - 2 inches in length and the Mystery Snails are about 1/2 inch in diameter or slightly smaller.
<Irrelevant to the aquarium size..>
Ok, now for tank info.... 10 gallon all glass aquarium with hood and light Aqua Clear 30 power filter for 10-30 gallons Tetra Whisper power filter for 2-10 gallons Heater (75 watt I think, it came with the tank set up) Air pump and 6 inch bubble stone 4 live plants (2 ribbon plants, a small dark green fern, & a water lily drop in the tank bulb that has leaves up to the surface now) Several fake plants 3 hideaway decorations Temperature stays between 80 and 82 Nitrate: 20 Nitrite: 0 Hardness: 150 Chlorine: 0 Alkalinity: 120 pH: 7.8
<Water quality sounds fine. Shame the tank is too small.>
All I have is one of the 6-in-1 dipstick type test strips, there isn't an ammonia test on it. After reading through your site I know I need one of the vial type test kits but PetSmart was out of stock the last time I went in. Do these usually include an Ammonia test or is that one separate?
<You don't need an ammonia test kit. A nitrite test kit is fine. If nitrite is 0, ammonia is probably 0 too.>
Also, water changes are twice a week (2-3 gallons each time) and the gravel vacuumed once every 2 weeks because it usually takes me too long to get the 'self-start' function working and I don't want to stress the fish out too much swooshing it around in the tank. Fish are fed small amounts 2-3 times a day with either TetraMin Tropical Crisps, Tetra Freeze Dried Blood Worms (3 times a week), or a strip of Top Fin Natural Dried Seaweed (3 times a week).
Sorry this was so long, I just wanted to explain everything the best I could. Any help or advice you could give will be greatly appreciated! Thank you! Amy
<Done my best! Cheers, Neale.>

Mollies... the usual iatrogenic sources of trouble -- 07/16/10
Good morning,
<Hello Carly,>
We have 2 tanks. One is a 60L and the other is a 95L,
<Both tanks are much too small for Mollies. You honestly can't expect them to succeed in tanks this small, no matter what. Without upgrading the tanks, anything else I say will be pretty pointless. 115 litres (30 US gallons) is about the minimum for Mollies. Females may be kept on their own in slightly smaller tanks, including the 95 litre tank you have, but males will be absolute terrors. The 60 litre tank is of no value at all for keeping Mollies.>
The problem that we are having is that we have 4 balloon Mollie girls (Various colours) and 1 male. First of all the male is terrorising one of the females, he constantly mates with all but this one. And since he cant mate with her he chases her around and its starting to stress her out.
<Well, I'm sure ALL the females are pretty stressed. But yes, this is "normal" unfortunately, and what male Mollies do. Do you have floating plants in here? Indian fern for example? If the answer is no, then get some.>
She is smaller then the other females, but that all that different, she just doesn't want to mate with him! I've noticed over the last two days that she looks as if she is starting labour, then everything closes up again, is this from the stress of the male?
Should we remove the male?
<I would.>
The other thing is, the male he is definitely a Dalmatian Mollie, but not a balloon like the shop said, he is very small, and slender and zips around like a dart.
<Balloon Mollies are obviously deformed. When people bred them they chose deformed fry, bred them together, and over the generations produced more and more deformed Mollies. It's pretty sad really. One problem is, as
you've noticed, female Balloon Mollies can't swim fast, and that means they can't get away from the males. Healthy Mollies are streamlined, fast-moving fish, which is part of the reason why they need quite large and spacious tanks.>
Any idea what breed of Mollie he could be, or is he just a junior?
<The deformity that characterises Balloon Mollies is obvious almost from birth, so I'm guessing you have a healthy, normal, and I'd argue luck Dalmatian Molly that hasn't got the genetic flaws that deform the spine and give rise to the Balloon Molly.>
Last question: We had a red wag tail platy gave birth to 150 fry in one sitting, then died a few days later. Then we had a case of whitespot, and only have 30-40 babies left. They live in a breeder trap but still more die, we have treated the whitespot, but the fish still flash in the main tank, what are we doing wrong?
<Difficult to say without some data. Platies need hard, basic, cool water; you're aiming for 10+ degrees dH, pH 7.5-8.5, and a temperature between 22-25 C/72-77 F. If kept in soft water, acidic water, or overheated water,
they won't do well.>
4 Female balloon mollies, 1 male
4 female guppies, 1 male
5 neon tetra,
4 green neon tetra
<Neons and Green Neons are not only incompatible with one another, but they're totally incompatible with Mollies. Neons need soft, acidic water at a cool temperature; 3-10 degrees dH, pH 6-7, 22-25 C. Green Neons also need
soft, acidic water, but must be kept water, 25-28 C/72-82 F. Trying to keep both together almost certainly means one or other is stressed.>
1 Bristlenose Pleco
<Need the same things as Neons.>
3 Female Platies
1 male
2 2month old juniors
2 Female fighters
1 male
<Mollies need warmer water than Platies, and harder water than either Neons or Green Neons. Please, for the sake of your fish, read about the needs of your fish BEFORE you buy them.>
60L Tank
8 Rummy nose tetras
1 Male fighter
2 frogs
1 albino red tailed shark
1 apple sail
1 albino bristle nose Pleco
<I feel sorry for the Red-tail Shark and the Rummynose Tetras; both these species have no business in a tank this small; even one three times the size would be cramped for them.>
Both tanks are cycled, and read at:
PH: 7.0
<Much too low for Mollies and Platies; no wonder the fry are dropping like flies. The stress on your Mollies could be down to this. Do please understand hardness, carbonate hardness, pH, and their importance to livebearers.
Water changes done weekly or more frequently if needed.
Thank you for reading my rambling.
<Happy to help. Good luck, Neale.>
Re: mollies 716/10

Good Evening,
Thank you for your reply, will take care full notice of what you have said, I have a 450L put back which I am paying off and hope to have with me asap.
The fish will be re-arranged as to there needs. Once again thank you for your knowledge and website.
<Glad to have helped. Good luck, Neale.>

Black molly with possible intestinal parasites (RMF, any ideas?)<<Mmm, none diff.>> 6/18/10
Hi Crew.
Ive noticed now that one of my black molly looks as if she is trying to expel her own intestines, for lack of a better phrase. There is a large whitish/slightly pink sac trailing her, and I¹m seeing signs of intestinal parasites with some of the other fish (stringy white feces). Ive attached a photo. Apologies for the quality, but hopefully it conveys what Im looking at a bit better.
<It's really not sharp enough to be sure. But my gut reaction is that, if this is a female, the pink "sac" is actually some part of her reproductive system. I have seen something similar with one of my halfbeaks, where the embryos died and the uterus formed a big blob outside of her vent. Whether the death of the embryos caused this, or something caused the uterus to deform, thereby killing the embryos, I cannot say. Neither do I know the causes. In this case, she died within a day or two.>
I have some Jungle anti-parasite food with Praziquantel and have started to treat the whole tank. I¹ve never seen anything like this before, so I¹m looking for confirmation that this is, in fact, parasites.
<Camallanus worms are not uncommon among farmed livebearers, but they are distinctive. I don't think that's the problem here.>
What are the chances that she¹ll recover or should I euthanize her if she doesn¹t seem better in a few days? I can only imagine it¹s painful, though she doesn¹t seem to be put out much.
<Yes, I would probably euthanise this fish.>
A bit of background: I did a water change/gravel vacuuming on Monday (45%), changed the filter, the whole shebang. Next day I lost two fish.
<Hmm... changing the filter sounds ominous. Do remember, filter cleaning is something to approach as gently as possible. Despite what the manufacturers recommend, you don't need to replace biological media very often, perhaps once every 5-10 years in the case of properly maintained sponges and ceramic noodles, and even then, no more than 50% within a 6-week period. Carbon and Zeolite are useless in most freshwater aquaria, so you shouldn't need to use them at all.>
I give the dead ones a look over, they look quite healthy. Test the water, everything is fine (ammonia and nitrites both 0). The next day, I lost 4 more fish. Did another water change and added back the cichlid mix. No further losses thus far. Not sure if this is important or not, but all of the fish that I¹ve lost have been from the same generation.
<If they're 5+ years old, then they may simply be old, and it's not uncommon for fish of a certain age to all die within a few months. On the other hand, if they're relatively young fish, then I'd be looking at sources of toxins such as insecticides or paint fumes, sudden pH changes, or non-zero ammonia/nitrite levels.>
Here are the specs on my tank:
27 gallon, long
Ammonia = 0.25
Nitrate = 5.0
Nitrite = 1.0 (I¹m surprised at this after such a recent water change/gravel cleaning. Any insight there?)
<Both the ammonia and nitrite levels are dangerously high. Make sure you haven't stressed the filter bacteria by cleaning the media too thoroughly. Simply rinsing media in buckets of aquarium water is all you need do. Naturally, review whether the tank is overstocked, under-filtered, or the fish over-fed.>
PH 8
Temp 80F
SG = 1.007
<These sound fine for Mollies, though you really don't need such a high salinity for good results. SG 1.003 is ample. If you choose to lower the salinity, do so gradually so that the filter bacteria can adapt, i.e., across a couple of months.>
Probably going to do another water change here shortly to see if I can get the nitrite level down and double-check that the filter is working properly.
The water has been clouding up quite quickly after each water change,
<Can be a sign of both diatom and bacterial blooms, the latter being alarming.>
but this seems to happen every 3-4 months (maybe it¹s something about my city¹s water?).
<Unlikely, but do make sure you're neutralising ammonia, copper and chloramine, not just chlorine, if your tap water contains these.>
As always, you guys are fantastic, and I appreciate your time and efforts so much.
<Glad to help.>
<Cheers, Neale.>

Small question, Molly hlth. 6/7/10
I just had a small panic attack that was definitely calmed by this question and answer:
"*Whirling Disease 09/04/2008 *Hi, I woke up this morning and went to feed my fish... 20 gallon tank - 3 Danios, 3 albino Cory cats, 3 Otos, and a Betta. Freshwater - Ammonia, Nitrates, Nitrites all 0. pH 6.8. I did a 20%
water change yesterday. Temp 78.
<All sounds fine.>
... when I looked in the tank, one of the Cory Cats was whirling and zooming around the tank. Then just stopped and lay on the bottom of the tank. I immediately separated him into a quarantine tank, where he whirled around again, and now is dead - about 30 minutes start to finish. From what I have read this morning, sounds like Whirling Disease.
<What fish farmers call Whirling Disease is caused by a particular parasite by the name of Myxobolus. Now, this parasite can only get into a fish via its food, specifically live Tubifex worms. Unless you've used Tubifex worms
(does anyone these days?) then it is extremely unlikely you're actually dealing with Myxobolus. Similar symptoms -- loss of co-ordination, nervous swimming -- can be caused by a variety of other things, including poisons and poor water quality. Because Corydoras are air-breathers, they are especially sensitive to things in the atmosphere, such as bug sprays and paint fumes.>
My question is this - what is going to happen to my other fish? I took the cat out before he died, but only minutes before this happened. Should I remove the other Corys just in case (I just got them and the Otos on Saturday)? I didn't quarantine them first b/c I only have a 2.5 gallon tank to do that in - I wasn't sure if that was okay to keep them in for a few days. Should I do another water change? Do I remove all of the other fish?
If I have to do this, what do I do about cycling the tank to keep the other fish safe? Or do I just wait and see what happens? Please advise. I'm having a nervous breakdown right now.<Right now I'd sit and review things.
Do you use Tubifex worms? Has anything potentially toxic been used in the house?>Thanks, Amy
<Cheers, Neale.>"
I was wondering, concerning the death of a molly I recently added to my tank, even though this is going to sound stupid--in addition to things like bug sprays and paint fumes, is it possible that Febreeze air spray could also cause these sort of symptoms? All of my other fish are doing fine as far as I can tell.
Thank you, Brie
<<Brie, it's difficult to be 100% sure, but unless you spray air freshener into the aquarium, tiny amounts in the air in a room aren't likely to cause you Molly health problems. When Mollies "whirl" the problem is usually what we call the Shimmies, and typically this is brought on by the wrong water chemistry or poor water quality. So I'd review those things carefully. Some people make the mistake of keeping Mollies in water that isn't hard and basic, and they rarely last long under such conditions. The addition of marine salt mix, while not essential, is very useful.
Cheers, Neale.>>

Dalmatian Mollies, and assorted other queries... hlth. 6/7/10
Hullo, I would like to inquire about the usual coloration of Dalmatian Mollies. I purchased three smaller ones, still babies really. One, the male, is black with white flecks. The other two are most likely female and white with black flecks. When I purchased them, they had gold flecks as well, and while the flecks have not spread, or grown in any way, I have become rather paranoid as to whether they have Velvet.
<Velvet is usually accompanied with "flashing", where the fish flicks itself against solid objects. Also, fish with Velvet commonly breathe heavily because the parasites infect the gills, often before the appear anywhere else.>

There are also two larger Sunset Fire Platys.
<Do be aware that Platies require cooler water than Mollies, and unlike Platies, Mollies generally do better in slightly saline conditions; the two species make poor choices for the same aquarium>
(One of which I fear is pregnant), neither of which have developed gold flecks, nor came with them and the Platys and Mollies were in the same tank at the Fish store. An additional inquiry; the male is apparently a vampire, or zombie if that suits you. He was caught by mistake with the two Platys and I took him as well because he is gorgeous. For two days he was frisky, then to all appearances, died. He was motionless, and wedged within a shell
in the tank.
<Moribund fish often drift into shells; take care not to assume he got stuck and thereby became sick or damaged.>
When I went to remove him, he came back to life with a vengeance, and for a day was active; then he 'died' again-to the point I actually poked him and he did not move until I tried to remove him. Then I purchased the two white-base Mollies, and he is now constantly active and for all intents and purposes happy. (Though all three are slightly neurotic when I turn the airstone off for any period of time despite the adequate filter and many live plants for oxygen). Is there a possibility to overcrowd a tank with Plants?
<Does depend on the plants. Biogenic decalcification can happen when certain plants, e.g., Elodea and Vallisneria, are kept, and if sufficient carbonate hardness is removed, pH will drop rapidly. Under normal conditions plants have almost zero impact on how much oxygen there is in the aquarium. The idea they are "oxygenators" is an erroneous one; they are not, at least, not under aquarium conditions.>
(other than the obvious being you cannot see into the tank-I do not mean that many) I have two small fern (less than three inches high) and a grouping of three or so large leafed plants about a palms height. If my platy is pregnant, I intend to let nature have at with the fry, but also want to give them a fighting chance as this tank is supposed to mimic a natural setting to the best of my abilities. (I am working on replicants of all my favorite diving sites and this is the first). Needless to say, these plants are living. ~RJ
<Time to do some reading.
Cheers, Neale.>

disorientated silver Sailfin molly 6/7/10
I have a 110L tank which has been well established for about 6 months now.
I have 1 male silver Sailfin molly, 2 black Sailfin molly male and female, 2 female black molly, 4 swordtail 2 male 2 female, 1 rainbow shark and a flash Plec.
<A lot of fish for this aquarium, and not 100% compatible. For reasons stated at least twice this morning already, Mollies do best when given somewhat warmer and more saline conditions than Platies and Swordtails.
While all livebearers will tolerate a little salt, the Rainbow Shark and the Plec will be rather less happy about that.>
As I said this is a well established tank and I also have several 4 week old fry which are all doing well and finally coming out of hiding and getting on fine. I took a water sample to my local shop for testing last week, as I was adding the Plec, and they told me my ph level was 7.5 and my nitrite and nitrate levels were pretty much non existent.
<"Pretty much non-existent" isn't zero, and zero nitrite is essential.
Nitrate levels above 20 mg/l do seem to cause problems for Mollies in the long run.>
I keep my tank purely freshwater rather than brackish as I have always found in the past there was no need to add salt and have always kept mollies in my other set ups without any problems.
<You're one of the lucky ones then. Do understand Mollies don't need "brackish" conditions, but a therapeutic 2-3 grammes of marine salt mix per litre of water does lead to better success. Always has done, and no-one anywhere argues that adding salt is harmful. The difference of opinion is whether the use of salt is essential. My advice is that since it never does any harm, and something like 50% of the time makes Mollies easier to keep, it's the wisest approach.>
This weekend I have added 2 small airstones for decoration only, but when I switched them on only at a very low level, within seconds the male silver Sailfin molly got very disorientated and, although still very active, kept tipping over nose first and upside down.
<Can't see why this should be a problem, unless the air was either [a] introducing airborne toxins such as paint fumes; or [b] disturbing decaying organic matter on the sediment that then started to consume the oxygen in the water very rapidly.>
He was still able to right himself, but not for long before he tipped over again. As soon as I turned the airstones off, again within seconds, he was fine and although slightly disorientated for another hour or so, he is fine now. All the other fish in the community are fine and unaffected. Can I just add he did not at any point swim through the bubbles, but many of the others did and remained perfectly ok.
<Indeed. Fish tend to avoid air bubbles, though some don't mind them.
Assuming this is a bog-standard air pump, it's unlikely you're super-saturating the water with oxygen or nitrogen, so it isn't likely you're causing distress that way.>
Although I am not the most educated in aquariums, I have always been very successful with Sailfins and mollies over the years. I have not come across this before with any others I have kept, and as he is my favourite and in my opinion the most attractive, I am really keen to get to the bottom of this.
<No obvious reason for this at all.>
Thank you in advance for any assistance you may be able to give.
kindest regards
<All very curious. Cheers, Neale.>
Re disorientated silver Sailfin molly -- 06/09/10

Hi Neale
thank you for your very quick reply, unfortunately the above mentioned molly died over night.
<Too bad.>
I did my own test on the water and the results I got were PH 7.5 ammonia 0 Nitrite 0.1 mg/l
<This is dangerous, especially to Mollies. Zero nitrite and ammonia are essential.>
and Nitrate 10 mg/l. There was no major disturbance of any sediment and no paint fumes and it is just a small standard pump. Apart from that I have no more information to give all the other fish are perfectly happy. Once again thank you very much for your help.
kindest regards
<Cheers, Neale.>

Platy, Molly and Frog in 1.5 gallons; ooh, surprise, they're dying! 6/1/10
Hello :)
<Hello Kacy,>
I'm really quite new to this owning frogs and fish business.
<Indeed. Do read.
Do a degree, most problems come with keeping the wrong fish in the wrong-sized aquarium in the wrong set of environmental conditions.>
I have two African Dwarf Frogs, a Sunburst Wag Platy, and a Dalmatian Lyretail Molly.
<Mollies are not really compatible with these other animals. While Dwarf Frogs and Platies should get along fine provided the water isn't too warm, Mollies need much warmer water and typically need slightly saline conditions.
If you have hard water and keep the aquarium water very clean -- by which I mean 0 ammonia, 0 nitrite, and less than 20 mg/l nitrate -- the Molly may be okay. But it's difficult to predict.>
I've only had them for a couple weeks but the very next day after I clean the tank (1.5 gallon)
<Far too small; these animals WILL die in there. The frogs may be viable in 5 gallons, the Platies need at least 15 gallons, and the Mollies 20 gallons+. It's not just about swimming space, though that's important; it's also about social behaviour and their sensitivity to changes in water quality and water chemistry. Very small containers of water expose livestock to constant changes in conditions, and inevitably this leads to death. Me telling you anything else is a total waste of time unless you upgrade this aquarium to at least 20 gallons.>
it gets cloudy and this white, cloudy, cotton like weird stuff forms at the bottom of my tank.
<Fungus and bacteria consuming organic waste, essentially doing the same thing as mould on bad cheese.>
I have no idea what this is and it spreads really fast.
<Because the aquarium is too small, overstocked, and under-filtered.>
Within two days the water in my tank is so bad I can't see through to the other side and I think the nastiness of this mystery substance killed my other Sunburst Wag Platy, though I'm not too sure.
<You are wrong. Rather, the death of the Platy and the appearance of the white mould in the aquarium are both symptoms of the same problem: this 'aquarium' is far too small.>
I change the filter often.
<Meaning? Do you understand that filter media needs to be cleaned, not replaced, and that it takes 6 weeks for cycling to take place before the filter can effectively remove ammonia? Furthermore, in a tank this small, no amount of filtration will save the fish.>
I've tried using a product called Clear Fast by Nutrafin which says it is supposed to make a difference in the water within 3 hours. I've never seen a change for the better.
<Indeed not; you've replace lack of knowledge with blind faith in marketing. The Capitalist Way perhaps, but not particularly useful.>
Also upon reading the question/answers I've seen some people say they only feed their fish every other day.
<Depends on the fish. Frogs need not be fed every singly day, but Platies certainly should receive a small meal of algae-based flake food once or twice per day. Problem is, in a tank much smaller than 15 gallons, any amount of feeding Platies properly will overload the filtration system.>
Am I not supposed to feed mine every day? I feed my frogs little foggy bites from HBH (though they don't often eat that, they do eat the fish flakes). Is that bad?
<Least of your problems.>
Thanks for your time,
<You need to do some serious reading. You ARE killing these animals through ignorance of their basic requirements. Hope this helps. Neale.>

Molly with Velvet?? 5/26/2010
Hi I have a 26 gallon brackish water
<How brackish? Velvet, freshwater velvet at least, is not especially salt-tolerant, though more so than Ick, and above SG 1.005 it is relatively rare. So one thing to check/do is raise the salinity to SG 1.005 (9 grammes marine salt mix/litre) and see what happens. Otherwise you'll have to use the standard copper-based Velvet medications.>
tank with 1 full grown black male molly and about 20 fry. I also have a 10g brackish quarantine tank that has a female black lyretail molly (she is the mother of all the fry in both tanks) and her 6 new born fry. I decided to separate the female because I know she still has more babies to give birth to and the male was chasing her and stressing her out.
<Keep at least 2 females per male.>
I had no choice but to put her in my q-tank, which now leaves me no place to treat sick fish. Two days ago, I noticed my female molly in the 10 g tank covered in gold. The fry seem fine and have only the usual gold coloring under their belly (they were born that way). I am assuming it's velvet that has infected my female molly.. What do you think?
<Velvet should be distinctive. Look for fine, icing sugar particles, golden tint, heavy breathing because of gill damage/infection, and periodic "flashing" as fish scratch themselves against solid objects.>
She is still very active and eating well. I have no idea how this happened...Anyways, I did a 50% water change, added Aquarisol to treat for velvet, removed carbon, raised temperature to 84 degrees, and added extra salt.
<How much salt? And for what it's worth, there are strains of Oodinium that are more tolerant of salt than others, and of course there is a marine version of the disease that exists from about SG 1.012 through to 1.025.>
She has shown no signs of progress. I am not experienced on handling disease when it comes to fry. Is there anything else I can do that will be safe for the pregnant molly & the fry? Also, is it possible that this color change could be a normal part of aging? Any input would be appreciated!
Please help, I don't want to lose any of my fish. Thanks.
<Cheers, Neale.>
Re: Molly with Velvet?? 5/27/10

Hi Neale,
Thanks for the info. Ok, I originally had 1table spoon of instant ocean marine salt (not sure if this contains Oodinium) per gal and now bumped it up to 2.
<Tablespoons per what? Cup of water? Pint? Litre? Gallon? Barrel? It makes a difference! One level TEASPOON is about 6 grammes, so 1.5 level teaspoons should be 9 grammes, and that's how much you want to add per litre of water. If you use gallons, there's 3.78 US gallons per litre.>
She does dart quickly; however, I removed all objects to avoid injury from scraping up against anything.
Is Aquari-sol an adequate copper based treatment?
<Contains copper sulphate, so should be, if used correctly.>
Also, the gold is not like a fine dust particle or crystal but more like the scale color.
<Sounds like velvet.>
I've attached several photos since they may be able to give you a better description of what I'm working with here.
<Too small to tell. Cell phones really aren't suited to photographing microscopic organisms!>
Prior to 3 days ago, the female was solid black. Although, when I first got her, I put her in a freshwater tank (ignorant to brackish systems and so forth and she began having the symptom of white spots) I moved her into the
10g and made that completely brackish and her symptoms subsided. She has been in a brackish system now for about 2.5 months and has been thriving.
This came up out of no where!
<My guess is that this system isn't as brackish as you think, and that's allowed the Velvet to become established. Ensure the salinity is 9 grammes per litre and see what happens. Cheers, Neale.>
Re: Molly with Velvet?? 5/27/10
Alrighty, I put 1 tablespoon per gallon,
<One LEVEL tablespoon is three LEVEL teaspoons, i.e., about 3 x 6 = 18 grammes. One gallon is 3.78 litres, so that's a dose of 4.8 grammes per litre, about half as much as you need to treat Velvet reliably.>
I thought I previously mentioned that, sorry.
<No problem.>
Now, I have it at 2 table spoons per gallon.
<Closer to the mark. Honestly, this is easier in metric. So can we do this in grammes per litre? There's a reason scientists use the metric system!
It's easy! When you say spoonfuls, I have no idea if you're using actual measuring spoons or mere cutlery, or whether you're using them heaped or level. These things make a difference!>
I would think this is sufficient for brackish systems??? Maybe not.
<For a brackish water system you'd be using marine salt mix at a dose of between 6-9 grammes per litre, i.e., SG 1.003 to 1.005.>
I took the pics with a camera and uploaded them, I made them small so that I could send all of them. I will try again now, so that you can see
<You seem to have send 24 images. I don't have that kind of time, and least not if I want to help other people here at WWM as well, so I looked at the first two. Didn't really show me clearly anything. It isn't obvious that this velvet from those images, so do take some time to look at photos of Velvet online, and compare against, for example, Slime Disease, Whitespot, ammonia burns, and genetic changes in the colouration of fish. Cheers, Neale.>
Molly with Velvet??? 5/27/10
Hi Neale,
<Hello again,>
Total of 37.85 litres (10g)
Total of 28.4 grams of salt (in the 10g tank)
37.85/28.4 =
approximately 1.33 grams of salt per litre.
<Not nearly enough to deal with Velvet, if that's the problem here.>
These pics should show you more...sorry to waste your time and I'm not trying to take time away from others.
<Not a problem. But one or two good images around 500 KB in size is what we do specifically ask for. This time you sent 20 MB of images! Apart from taking forever to download -- I gave up -- that blocks up our limited e-mail mailbox space. Please, we have these very minor rules in place for a reason, and not to be awkward.>
I'm just wanting to get a professional opinion. I'm sending this to you from another email to see if this will do the trick with viewing the pictures!
<See above. It's gone 10 PM here in England, and I'm about ready for bed. Downloading just one of your 4 MB images was taking forever, so I gave up. I'm not about to wait 10 minutes waiting for them to download... Forgive me.>
Thanks for the info.
<Glad to help. Cheers, Neale.>

Please help.: Mollies doing poorly in a FW system. 5/11/2010
I recently set up a fresh water tank (about 3 weeks ago). My tank size is a 55 gallon tank, equipment: AquaClear filter 70 (300 gph), Marineland Stealth Pro heater 200 watt, a double bulb T5 light fixture ( both bulbs are Coralife 28 watts each, one 10,000k, and one colormax) the aquarium also came with a light fixture with a bulb that I quickly replaced with a 40 watt Life-Glow 2, black diamond substrate.
<All sounds good there.>
I also have live plants, which are:
Aponogeton crispus
Banana plant
Walkerii crypt
Dwarf baby tears
Brazilian pennywort
Petite nana
Dwarf subulata
Red tiger lotus
Water sprite
Dwarf four leaf clover (recently ordered, waiting on arrival).

I use Flourish excel and Flourish tabs in the substrate. I keep my lights on for ten hours (have timers set up). Livestock so far include:
1 male Betta (which gets a long great with the other fish)
7 cardinals
5 harlequins Rasboras
5 cherry barbs
5 black Neons
3 bamboo shrimps
5 ghost shrimps
5 mollies

The fish seem to be doing great, they storm all around while feeding, I feed them frozen brine shrimp, tetracolor tropical flakes, and freeze dried blood worms (I alternate food type each day) once a day. My concern is for my mollies, they seem to do good some days and other days they just float at the surface or sit on the substrate at the bottom.
<These conditions aren't the best for them, also Mollies aren't an 'easy beginners' fish that is commonly claimed.>
They do eat every time I feed all the fish, and I see them from time to time nipping on the Mopani woods and rock in the tank. One of the females seems to have a pinched stomach, and one gold female already died. The temperature in the tank is a constant 76 F. I have zero ammonia in my tank, and as for the other readings, they are as follows:
180 GH ppm
0 KH ppm
6.0 ph <Way too low for Mollies.>

0 NO2 ppm
0 NO3 ppm
I had the water also tested in my local pet store to make sure I was doing the tests right and they also got the same results. The tap water in the area where I live is very hard. I purchased a water softener pillow but it didn't really do much.
<They never really do.>
I was also reading about mollies, and I discovered that they prefer some salt in their water (which I did not know before purchase, my mistake for not informing myself)
<They do. With good Mollies, you can actually adapt them to SW. I have two in my marine tank.>
So I went ahead and got some aquarium salt in put in the amount required for a 55g tank, but I also did some more reading and discovered that my other fish do not like the salt, so I did a water change, about 30%. One of the males wants to mate as he follows a female around trying to do so, and other times most just sit around with minimum activity. Is there anything I can do at this point to make their environment more to their liking without jeopardizing the other fish, say... like a common ground for all fish?
<All of your other fish should do fine in your setup. I would suggest getting rid of the mollies altogether, as the conditions that favor all of your plants and other fish are completely wrong for mollies.>
Can changing my GH, KH or pH help the mollies?
<Yes, but detrimental for your other livestock.>
Is salt necessary for mollies or will they adjust to water without it over time?
<Mollies need hard water and high pH. I would remove them. Have a read here: http://www.wetwebmedia.com/FWSubWebIndex/fwlivestk.htm and here:
http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm >
Please help.
Re: Please help.: Mollies doing poorly in a FW system. 5/12/10

Thank you Mike.
<My pleasure.>
I have one more question. Do you think it's possible to get my ph a little higher, within the same range my other fish enjoy, and get a positive result from the mollies? I hate to give them away, I just absolutely love them.
<Unfortunately, no. You could get the pH up higher, but the mollies still wouldn't really thrive. They like hard water with a higher pH. Their optimal environmental conditions are just completely opposite of the system you have, but perfect for the other fish in your tank.>

Fancy guppy harassing Silver Mollies (killed one already) please help! 4/20/10
I have been reading your page and find it very helpful, so I'm hoping you can help me with the situation I have now. I've had a 29 gal tank with 2 fancy guppies (male), 2 Red Wag Platies (female) and 1 female Black Molly (used to be 2, but the male passed away 2 weeks ago) for 2 months now. I just introduced a new Black Molly (female) and 2 Silver Mollies (both females) three days ago. All of the fish appeared very healthy. Healthy appetites, active, etc.
<Good. But do read about the needs of these various species, they are not entirely compatible in terms of, especially, temperature and salinity, and to a lesser extent personality, Platies tending to be less aggressive than
either Guppies or Mollies. Do read:
On the second day, one of the guppies were/are harassing the Silver Mollies. This morning I found one of the Silver Mollies dead.
<Hmm... may or may not be related to aggression; Mollies are sensitive to non-zero levels of ammonia and nitrite, and to a degree nitrate, when maintained in plain freshwater aquaria. If you look over our archives, you'll see we get a LOT of messages about sickly Mollies.>
I believe the guppy stressed the Molly to death and now he's "all over" the other one. All of my water levels are great
<"Great" is difficult to believe, since Platies need cooler water than Guppies and Mollies, and Mollies definitely need much harder water than either of these, and are much easier to keep, i.e., reliably healthy, in slightly brackish water.>
so I'm convinced the guppy harassed her to death and I'm afraid for the other one. I'm going back to get another Molly (pet store has a 14 day return policy) but I want to make sure it doesn't happen again. Any advice would be greatly appreciated.
Thanks, Bob
<Do read, review the needs of these species and act accordingly. Male livebearers of all types are aggressive, snappy towards one another and tending to harass, often to distraction, females. They aren't "picky" and a male Guppy will readily harass a female Molly. Choose species appropriate to your particular water chemistry, salinity, temperature. Then maintain sensible numbers, at least two females per male. Avoid mixing species if possible. Do add lots of floating plants to provide shelter for females and cover for less aggressive, picked-upon males.
Cheers, Neale.>
Re: Fancy guppy harassing Silver Mollies (killed one already) please help! 4/20/10
Thank you so much for the very quick response and very helpful information.
<Happy to help.>
I have been to the same place from the beginning and basically, they set the tank up for me. I was told, by them, that these fish were perfect to start a tank with.
<Not Mollies.
Platies are often good starter fish though. In any event, it's always wise to treat advice from a retailer -- whether selling fish or a car -- with some degree of skepticism. Double check things via books before spending your money.>
I had brought in a water sample to have it tested at the pet store and the gentleman (idiot) who sold me the fish said my water levels were "great".
<He may well be referring to zero ammonia or nitrite. But without knowing the water tests he did, and what the numbers actually were, "great" is a subjective rather than objective statement.>
That's why I had purchased 3 more fish. From reading the helpful information on your website, I realize now, that these fish require specific water conditions.

I'm heading back there this evening and since he is young I'll probably (hopefully) just scream in his face.
<Well, wouldn't be my approach... Politely explaining you now understand about differences in temperature requirements, salinity, social behaviour may be the way forward. Explain you're aiming for a set of conditions best suited to, say, Platies. So you're going to have moderately hard, slightly basic water at a temperature of 24 C/75 F. For that sort of tank Danios and Corydoras would be ideal tankmates, not Mollies or Guppies.>
Since I can't afford more tanks (and don't want more) he's going to buy ALL of them back. I thought I had done my "homework" by listening and taking notes from the pet store, but apparently that was in vain. I'm getting more and more angry as I'm writing this so, thanks again for all of your help.
Sincerely, Bob
<Don't get angry; become wiser. Cheers, Neale.>

Molly Fish Fry may have velvet. No, just env. as typical 4/15/10
I have a 26g aquarium with a two glow Lite tetras, 3 black Neons, 1 rummy nose, 1 small clown loach and a 8 baby mollies.
<Mmm, these last "like" very different water quality than the Tetras... hard, alkaline, and quite cool temp. wise...>

The fry are about 5wks old. I moved the mom and dad (two black lyre tail mollies, but not sure if they are gold dust) to a quarantine tank because they were showing symptoms of velvet (unless they are gold dust mollies).
<If Velvet, all the fishes would have it... be dead in short order>

It was suggested that I should put them in the Q-tank and add lots of aquarium salt since they were more than likely having a difficult time acclimating to my 26g fresh water aquarium.
<All mollies live in hard, alkaline water conditions, most prefer brackish settings>

When I moved them there, the symptoms subsided. The drastic gold shimmer went away. However, I do notice very few gold sparkles still on them and when their gills open, there seems to be a gold lining inside. I am only able to see this with the light of and the use of a flashlight. They have been in the Q-tank for about a month now.
I also added some aquarium salt (abt 2tbsp) to my main tank...the 26g. to make the molly fry a little more comfortable, although, they were born in freshwater so they seemed to be okay with that.
Here's the deal, every so often, the clown loach brushes up against the driftwood
<Natural behavior>
and I am afraid he may have external parasites. I do not notice a gold shimmer on him, but all other fish in the tank have a goldish shimmer. The molly fry only have the shimmer on their underbelly. But, the glow Lite tetras and the black Neons seem to show the gold shimmer as well. I am having a hard time determining if the fish have the natural gold shimmer and I never noticed it before, or I may be being paranoid now that I have the fry. I've never had fry before.
What are your thoughts on my dilemma? Also, if they DO have velvet...Can I treat the entire tank or will that harm the fry? I am not sure what to do.
<Mmm, you should read, have read here:
and the linked files above, to the point you understand Mollienesia basic husbandry>
I checked my levels and ammonia, nitrate and nitrite are fine. No other fish show any other symptoms (besides the gold shimmer) other than the clown loach who rubs against the drift wood but again, that is not often he does that.
Also, mom had a second batch of fry in the Q-tank and those fry (only abt 1-2 wks old) seemingly have the goldish shimmer on their underbellies as well. Could I possibly have two tanks with velvet??
<Highly unlikely... Read here as well:
and learn to/use the search tool, indices>
I'm nervous here. The mom and dad have not showed any signs of slowing down and still have on heck of an appetite. I would assume that if they had velvet, they would be showing more outward signs, but I may be wrong.????
<No, you are correct here>
Sorry for the massive overload of information and questions, I just have a lot going on with these fish and fry and I want to take the best course of action for this situation.
<No worries>
Thanks so much for any help you may be able to provide me with.
Sincerely, anxious fish owner
<I'd be setting up a separate Molly/Brackish system. Bob Fenner>

Sick Orange Mollies... Sys. 4/14/10
Hello there,
I'm hoping you can help me diagnose my sick mollies. I have a 55-gallon tank with many mollies - Dalmatians, black, white, orange, and many mixed - too many to count. The water is only slightly brackish - I add 1-2 teaspoons each week with about 20-25% water changes.
<One to two teaspoons per what? Per litre? Per gallon? If per gallon, this isn't even remotely brackish. One teaspoon is about 6 grammes of marine salt mix, which is what you should be using -- not tonic/aquarium salt. An appropriate amount of marine salt mix for Mollies is between 3-5 grammes per litre, i.e., a scant level teaspoon per 1-2 litres. That should give you a specific gravity of 1.003-1.005. If you need to convert these into non-metric units, go ahead and download my Brack Calc application for Mac and Windows and do the conversions yourself.
I recently (5 days ago) quarantined 4 of the orange mixed mollies due to orange cotton-like growths on their bodies. 2 of them have just one little orange growth (looks like a pimple) - 1 has it on his head and the other near the back of his body. The other 2 have several of these cottony, orange patches growing on the side on their heads and bodies.
<Water likely not hard enough, not basic enough, and not brackish enough. Do also check the water is also adequately warm, around 28-30 C being required for Mollies. Finally, review water quality. Mollies have no tolerance for ammonia and nitrite, and minimal tolerance for nitrate.>
Three days after I quarantined them, 1 of the mollies with just one growth has been laying on the bottom of the tank's gravel and not eating and having difficulty "breathing." The one with the most patches is eating but occasionally laying on the gravel.
<Dying without prompt treatment and correction of environmental issues.>
I'm feeding antibiotic food to them but haven't done any water treatments except changing water and adding 1 teaspoon of salt.
<Adding ordinary salt won't raise pH and hardness, which is why marine salt mix is what you need, e.g., Instant Ocean, Reef Crystals, or whatever cheap generic brand of marine aquarium salt is on sale in your pet store.
Medicating against Fungus and Finrot, e.g., with eSHa 2000 or Seachem Paraguard will be required.>
I've read about fungus but research shows that it's white or gray, and I cannot find anything about orange fungus. I've been researching this for 5 days, so this is my last resort. Please help!
Thank you,
<Do read:
Cheers, Neale.>
Re: Sick Orange Mollies 4/15/10
Thank you so much for your quick reply.
<No problem.>
I would appreciate a little clarification on the salinity of the water.
<Ask away.>
With the exception of the website you emailed to me, most websites recommend about 36 grams of salt per 38 liters of water,
and your recommendation is 114-186 grams of salt per 38 liters of water.
<Correct. Normal seawater has 35 grammes per litre; brackish water needs to be at least 10% that salinity, i.e., at least 3 grammes per litre. Anything less than that is pointless in this context (though it may be useful for minimising nitrate toxicity, etc.).>
Honestly, I do better with teaspoons and gallons, so this would equate to 6 tsp. per 10 gallons on most websites, and 19-31 tsp. per 10 gallons on your recommendation.
<Can I suggest you concentrate on grammes per litre? It's so much easier. This is precisely how marine biologists, even American ones, work. It's easy to remember 35 grammes of salt is in 1 litre of seawater, and given one level teaspoon is about 6 grammes, it's even easier to estimate how much you need. If you have a 38 litre tank, then at 3 grammes per litre that's 3 x 38 = 114 grammes, or about 9 level teaspoons. Easy peasy.>
Before I add the marine salt, I wanted to be sure I wasn't misreading your suggestions, since the 2 seem so different. Thanks again, Leah P.S. The website you emailed to me recommends 285 grams (47 tsp.) per 38 liters (10 gallons!)
<At 7.5 grammes per litre, yes, you'd use 285 grammes in a 38 litre tank, for a whopping SG 1.004. Put this into context please. 38 litres of seawater would have 38 x 35 grammes = 1,330 grammes. Cheers, Neale.>
Re: Sick Orange Mollies 4/15/10

You are awesome!
<Wish my girlfriends thought so.>
I think my last questions are- can I add the marine salt mix all at once or do I have to introduce it gradually over several days?
<The Mollies couldn't care less, but for the sake of the filter bacteria, add the salt over a day. I'd get a jug, fill with warm tap water, add a drop of dechlorinator, and then add the weight of salt needed for the whole tank. Then over the day, add a portion of that water to the aquarium, maybe six portions over the day.>

Oh, one more - I assume I replace the salt proportionally only with water changes.?
<Yes, but adding however much you need per bucket to each bucket of new water. So let's say you take out one 10 litre bucket of water. Add to the bucket of new water just enough salt for the 10 litres, i.e., 10 x 3 grammes or whatever. I mention this because some people make the mistake of adding enough salt for the ENTIRE aquarium, not just the replaced water, and that would raise the salinity too much.>
And finally, you recommended Seachem Paraguard to treat the orange cottony patches/pimples on the fish. I am already feeding Anti-bacterial food - should I use Anti-parasitic food instead and in addition to the parasite medication?
<If the Mollies have external symptoms of Finrot and Fungus, I'd use Paraguard, but there's no harm at all using both.>
Thanks so much. You've been most helpful!
Leah :)
<Glad to help. Cheers, Neale.>
Re: Sick Orange Mollies 4/17/10

Sorry Neale, but I have another question. I plan to add the marine mix to the 10-gallon quarantine tank to help the mollies get better. I also wanted to add it to my 55-gallon tank, but will it hurt my Pleco?
<Difficult to say. In theory, Plecs come from freshwater habitats and are should not be kept in a brackish water system. But in practise, at least some Plec species that have got loose in Florida do seem to have adapted to slightly brackish water habitats where things like Mollies and killifish live. Nonetheless, Mollies are, fundamentally, incompatible with most catfish. If you must keep catfish with them, you have to choose those species that tolerate slightly brackish water, such as Hoplosternum littorale.>
I've had him for several years, he's VERY large, and I wouldn't want to harm him.
<Keep them in separate tanks.>
If it's better not to use as much salt in the larger tank, how can I re-introduce the sick mollies back to freshwater without harming them.?
<No sure fire way. I dare say at a very low salinity, perhaps 1-2 grammes per litre, a hardy Plec species won't be too fussed, but above that you'd be pressing your luck. Balancing enough brackish-ness to ensure perfect Molly health whilst not stressing the catfish will be a tough needle to thread.>
Thanks again!
Leah :)
<Cheers, Neale.>
Re: Sick Orange Mollies
Thanks again Neale,
I believe my most important question now is - can I, and if so, how do move the mollies back into their freshwater tank after being in the brackish quarantine tank?
Leah :)
<Some variation of the drip method will work fine. But as stated repeatedly here and in virtually every aquarium book ever written, Mollies are unreliable in freshwater tanks. If you must keep them in freshwater, keep them warm [around 28-30 C seems best for fancy Mollies] and in water with zero ammonia and nitrite, and near-zero levels of nitrate. The water hardness must be very high, 15+ degrees dH, and a high carbonate hardness is essential, 5+ degrees KH. Let's be absolutely clear that Mollies are a poor choice for the average community tank, and I don't recommend keeping them in freshwater at all, despite being mostly freshwater fish in the wild. Cheers, Neale.>

Curious, mollies, killing them 4/11/10
You are all so helpful.. I've been reading your site since I started keeping mollies, about a month ago.
I inherited a tiny tank (1-3 gallon, not exactly sure) and went into a pet store. I told them the specs of my tank, unheated, tiny, etc., and they sold me mollies.
<A poor choice for sure. These livebearers need a minimum of metabolite build-up... a few gallons will certainly see them self-poisoned>
Because I didn't know any better, I bought two mollies and kept them for as long as I could, which was a surprising
two weeks. Of course, the cold water didn't suit them, and neither did the tiny tank. I learned that part by reading your site when my original two (Spartikus and Alvira) started going vertical and swimming on their sides. Needless so say, they died.
I wanted to try again. I filled up a 15 gallon tank, put in "Prime," which is supposed to be the chemical remover as well as the good bacteria.
<Still have to wait for it to cycle...>
I let it run with the heater and pump for 15 hours, then bought some more fish.
<Won't work>
I bought three mollies (1 male balloon, 1 female black lyre-tail, 1 female saffron) and a clown Pleco.
<Nothing for this last to eat here>
This was on a Monday. By Tuesday morning, my balloon molly had died. Before he died, he kept tipping over onto his side at the bottom of the tank. I called the pet store that I bought these ones at (Not the pet store that gave me terrible fish advice the first time!), and they said it was likely his swim bladder.
When he died, I brought him in as well as a separate water sample. I don't know how to test the water myself, so I had them do it and they said all was good (I didn't get specific numbers from them, sorry).
On Wednesday, I bought a male cremesicle molly.
To avoid my females getting territorial, before releasing him from his free-floating bag, I moved all the "furniture" around. He swam around normally all day, but by late night he was lying at the bottom of the tank. I knew he
probably wasn't going to make it, and I was right. Once again, my water levels were tested and confirmed to be fine. The fish "expert" at the store said that it could have just been stress of transferring, or once again, his swim bladder.
<... dismal>
I then bought a new balloon molly.
This male is mostly orange but has white stripes (really pretty). I didn't really pay super close attention to all his markings, and now I'm a little worried... By his top (dorsal?) fin, he has either several white spots or a white stripe.. It's really hard to tell. I'm concerned he may have ich, although I can't say for sure. He hasn't been banging into the gravel or anything, and he swims normally. All my mollies have been swimming normally, spending time in all levels of the tank - mostly swimming in the middle. Is there any way to tell for sure?
<See WWM re>
If not, will treating for ich cause any harm if there is no parasite present?
<Will likely poison these animals further>
My temperature is always between 76 and 80 F, only ranging a little because of crazy ranging house temperatures.
I don't add any salt to the water, because they were in freshwater at the pet store and I don't want to stress them out this early (I've only had these fish for a week).
My tank is 15 gallons, has a heater, pump (with foam, carbon, charcoal), light, and fake plants only.
I only feed my mollies every other day, and they sometimes eat the pleco's food if he leaves it alone for any length of time.
Any advice is much appreciated :)
p.s. I do not have a spare aquarium to quarantine him :(
<... Please read here: http://wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above. This system is not cycled... there are (self-induced) troubles ahead. Bob Fenner>

Sick molly fish, 3/30/10
"Hi, I have a 150l tank that`s been set up for just over 3 months now. We let it cycle for 1 month then added 5 molly fish, we now also have 10 molly fry a few weeks old (1.5-2cm in size)and no other fish.
<Mollies are tough to keep in freshwater which I assume you are doing here.>
A week ago we noticed one of the white female mollies swimming strangely and at times her head seems to shiver quickly for a few seconds. Other than this she is behaving fine with no growths, marks or reddening on her body
and fins, she was as active as usual and feeding okay (today she seems a little more lethargic) but her tail is bent downwards and isn`t being used as she swims, it appears to just be dragging along. I usually do a 20% water change weekly but stepped it up to about 20% every other day since we noticed her swimming funny. I`ve also added some Interpet treatment for swim bladder infection but I`m not convinced this is the problem so wanted to check before I redose?
<This is not helping here, may be worsening the fish's condition, I would not redose.>
She's shown no major deterioration or improvement that I've noticed so far but I'm now worried 2 of the other mollies are showing similar things just not as severe. She doesn`t seem to be pooing as much as the others and from
reading I`m wondering whether it could be parasitic, TB or constipation but I just can`t tell? I`ve noticed one or two of the fry rubbing and flicking against rocks now and again but nothing frequent and there's no visible white spots.
<Sounds environmental, these fish in fresh water are very sensitive to nitrate.>
Any help would be much appreciated, completely lost as to what to do!
My tank is 150l and kept at 26`C with a tablespoon of aquarium salt added per 19 litres (though almost certainly going brackish once we've sorted this out) and all water chemistry appears fine.
<What is your nitrate reading, fine leaves too much for interpretation. I would being transitioning these fish to brackish conditions soon, as I think this will go a long way towards improving their conditions. Mollies in fresh water can be very tough to keep, in brackish conditions they are almost bulletproof.>
Thanks in advance...

Molly 3/20/10
I have a 10 gal tank with 2 molly's 2 harlequin 2 horse faced loaches. My female molly has "shed" her skin on her tail and it has a sac of something in it. The male's spine is crooked. What is happening!?
<Hello Christine. Without a photo, it's hard to be sure what you're describing here. But poor environmental conditions are surely part of the problem. Harlequin Rasboras need soft, slightly acidic to neutral water.
Those conditions are lethal to Mollies. It's impossible to keep them in the same aquarium successfully in the long term. Any aquarium book should have made this clear to you. Their preferences are well known. Horseface Loaches will do well in either type of water conditions, and actually occur in slightly brackish water as well as freshwater, so they're surprisingly good companions for Mollies. On top of water chemistry problems, your aquarium is FAR too small for these fish. Even Harlequin Rasboras would need at least a 15 gallon tank, and realistically 20 gallons upwards. Mollies a bit more space than that, since they're very sensitive to high nitrate levels
and background acidification, both very likely in small tanks. Horseface Loaches are quite large fish, and potentially antagonistic towards one another, so even a 40 gallon tank would be pushing your luck when it comes to keeping two specimens. All things considered, I think we're looking at negative reactions to poor husbandry, and the solution is [a] reading about the needs of these fish; and [b] providing those conditions. Some type of medication against Finrot and/or Fungus will likely be required as well, but alongside dramatic improvements in living conditions rather than instead of them.
Cheers, Neale.>

Don't know what is wrong with my molly. 3/20/10
Dear WWM,
I had an outbreak of ich which I successfully conquered! I just got back from being out of town for a few days and noticed something wrong with my mollies head/back right before the dorsal fin- she has what looks like scrapes we humans would get from a fall. It appears to be all scales are there though, she moves so fast its hard to see and examine. Looking from the back forward, they looked raised and there is also something white within the scales or under them. I have looked at some various other diseases and I can not really seem to find something to match. She acts more lively than ever I feel, always swimming around and eats like a pig.
Please help me, I am worried and want to fix this early if I can!
Thanks in advance,
<Hello Sarah. Do start reading here:
Mollies are sensitive fish when kept in plain freshwater conditions, especially in soft water. If you must keep them in a freshwater tank rather than a slightly brackish one, it is crucial that the hardness and pH are high (15+ degrees dH, pH 7.5-8) and that the water quality is extremely good (0 ammonia and nitrite, <20 mg/l nitrate). A relatively high water temperature, around 28-30 C, also helps. When kept in sub-optimal conditions, Mollies are prone to things like Finrot, Fungus, excess slime production, Mouth Fungus (Columnaris) and something called the Shimmies.
Cheers, Neale.>

black mollies, hlth., env.... the usual 3/1/10
I have 3 adult black mollies and 3 young mollies- about 8 weeks old. The tank was set up in December and we received the adults before it cycled (I've learned a lot about having fish since then)
<Good. Now, I have to be frank here, Mollies are appalling fish for new aquaria. They are very intolerant of nitrite and ammonia. They are poor choices for average freshwater aquaria having very specific needs. Mollies need hard, basic water with zero nitrate content. The water chemistry has to be "liquid rock", pH 7.5-8, 15+ degrees dH, 10+ degrees KH.
I notice with some alarm that you're not providing anything like these conditions, and that's why your fish are sick. Mollies are much hardier in brackish water, but that requires the use of marine salt mix at much higher levels than most freshwater fish will tolerate, so this isn't viable for mixed community tanks (though you can of course have a brackish water community of Mollies with gobies, sleepers, glassfish, guppies and other small to medium sized brackish water fish).>
The fry had large bellies and the adults had white spots (not ich)-- I checked and the nitrites and nitrates were off the charts.
<Not good. In freshwater conditions ammonia and nitrite MUST be zero, and nitrate as low as possible, ideally zero, and certainly less than 20 mg/l.>
I did an extreme water change I read about online and the fish all seemed to get better. The young mollies still have white bellies- and I want to make sure that is normal.
<Colour varies a good deal, especially with crossbreed Mollies.>
The adult female seemed to release some kind of egg sack recently-- her gills seem to be getting more silver- is that normal?
<Not really, no. But I wonder if you mean the gill covers are silver, and this may be natural colouration, or may be excessive mucous production. The latter will appear grey or off-white rather than metallic silver.>
My biggest concern is with one of the adult males (KD). Last week his back fin seemed paralyzed. I treated the tank for 5 days with Maracyn with the coal filter removed to treat the white spots I was seeing. I also bought a new heater to control the temperature fluctuations. KD started using his tail more the last few days, but today we introduced a Plecostomus and KD's scales on the back half of his body are white and seem to be sticking out; also looks like there some kind of tissue coming out of the gills -- swear he was ok this morning. His back fin looks like a feather when its been played with too much and the barbs get stuck together. I have separated him, but have no idea what he has or how to treat it. In writing this, he's flipped on his side, dont know if he'll make it.
<He is severely stressed. In the right conditions he'll pep right up, but unless you fix things, this isn't going to happen.>
Tank size: 20 gal
PH: 7.6
<Far too low. That's about 2 degrees KH, whereas you're actually after about 10 degrees KH.>

hardness: above 300
nitrite: between .5-1.0

Included pick 2 picks of young mollies & 2 of sick fish
<Do please send smaller images. We have limited e-mail space, and you sent 15 MB of material, and once that allowance is filled, other folks have their messages bounced back. We do specifically ask for pictures no bigger than 500 KB, right where you found our e-mail, and we're asking not to bloody minded, but so that everyone has a chance to send their messages to us every day.>
<Much reading and work to do. If you're only keeping Mollies in this tank, then switching to brackish water, around SG 1.003 at 28 degrees C/82 degrees F (about 7 grammes of marine salt mix per litre) will help significantly. Otherwise, harden the water using the Rift Valley salt mix at about 50-100% the dose recommended depending on the other tankmates (other livebearers are fine with very hard water, but tetras and other fish won't be). Water quality needs to improve dramatically. Cheers, Neale.>

Molly Question... hlth., gen., reading -- 02/25/10
We have a 5-gallon tank and have had 2 Balloon-bellied Mollies in it for 6 months.
<This tank is far too small for Mollies. Honestly, they really do need quite big tanks. Mollies generally require at least 20 gallons, and realistically 30 gallons to do well. Balloon Mollies do tend to be a bit smaller than regular Mollies, but they're just as sensitive to poor conditions as any other kind of Molly. Indeed, because they're so deformed and inbred, they're likely to be more prone to disease.>
Our orange colored Molly seemed to develop Ich (white spots on its top and back fin) and responded well to Rid-Ich treatment.
<When you keep Mollies in slightly brackish water, Ick and Velvet shouldn't happen at all. It's a good reason to keep Mollies that way, with about 6 grammes of marine salt mix added to each litre of water.>
Some time has gone by (about 2 months), but now it has developed black spots on its top fin.
<Black spots may be genetic, but they can also be ammonia burns. In a 5-gallon tank, poor water quality is VERY likely.>
It is swimming very fast and seems to be doing everything it can to keep itself from going upside down.
<Again, because these fish are deformed, they're more likely to succumb to various ailments, and the deformation of the spine and swim bladder means that complaints like constipation can really mess up their equilibrium.>
It also seems to anchor itself near the filter more than usual.
<May be "the Shimmies", a common disease among Mollies caused by poor water quality and the wrong water chemistry.>
We checked with our local pet store, but no one seems to know what is wrong or what we should do to treat it.
<Really? I find that hard to believe. Mollies are very well known for their sensitivity to poor environmental conditions, and if you told them these Mollies were in a 5-gallon tank, any half-decent aquarist should immediately suspect this.>
Our levels all appear to be in normal and good ranges.
<No idea what this means. What are the numbers? For Mollies, the following are essential: 0 ammonia; 0 nitrite; less than 20 mg/l nitrate; 15+ degrees dH general hardness; 10+ degrees KH carbonate hardness; pH 7.5-8; temperature 28-30 degrees C (82-86 F). While maintaining them in brackish water isn't 100% essential, about 50% of the time it's the difference between success and failure, and if you're only keeping Mollies, then maintaining them in brackish water is a no-brainer. Aim for 6-9 grammes marine salt mix per litre, SG 1.003-1.005.>
At one time we had higher nitrates, but that has since stabilized. Can you tell me what is wrong with our Molly? Just yesterday, we resumed the Rid-Ich (removing the carbon filter) because we didn't know what else to do.
<Read. Start here:
Thank you.
<Cheers, Neale.>

Hello WWM -- 02/22/10
Thanks for all of your information on mollies and such. I have been an aquarists for a couple of years now, but I have just gotten two mollies. I have a 27g freshwater aquarium and was not informed that they needed brackish water to survive.
<Indeed. Not 100% essential, but I'd guess essential a good 50% of the time. Certainly, the more casual you are as an aquarist, the more useful brackish water conditions will be, since the saltiness offsets minor problems related to water chemistry variations, nitrate toxicity, and so on.>
One black and one lyre tail (black and white). I have only had them for two days and I recently noticed a white clear bubble on the outside of the black molly's eye.
<Very common with Mollies, for some reason. It's typically caused by physical damage to the cornea, e.g., when the fish was netted, and because Mollies have a weak immune system when not kept in perfect water conditions, the cornea often becomes infected. I've seen more Mollies with damaged eyes than almost any other fish.>
It is only on one eye and doesn't seem to be affected the fish much. Any suggestions for what this is and what I can do to help?
<Do read here:
Essentially, you'll be treating with Epsom salt, optimising water quality, perhaps treating with an antibiotic, and hoping for the best.>
Also, the lyre tail has a gold-ish tint to its color...is this part of the lyre tail appearance or is this a possibly of velvet disease?
<Velvet is common among Mollies kept in freshwater. Again, brackish water conditions prevent Ick and Velvet. One typical symptom of Velvet is "flashing" and laboured breathing, both caused because the Velvet parasites irritate the gills.>
One other concern is that the lyre tail is chasing the black molly and forces it to stay ducked off behind the filter.
<Males are mutually aggressive.>
I was under the impression that these were not aggressive fish and am concerned with the behavior.
<Who told you Mollies were peaceful? They aren't. In the wild Males drive off rivals so they can monopolise access to the females. The fact the male fish are smaller than the females and more likely to be eaten by predators only adds to their fury. Even females can be a bit temperamental; I'd recommend keeping at least three females, with or without one male. For larger groups, multiples of this sort of ratio will work well.>
My objective is to have a nice, friendly, community tank and do not want any of my fish to be forced to stay out of sight, in order to pacify other fish.
<Mollies aren't community fish.>
Any suggestions? The lyre tail does not do this to any other fish but the black molly. My tank is maintained at 78 degrees always. I have a heater and good filtration system. Water conditions is good.
<Define "good". Mollies have very specific requirements. Firstly, they need very warm water, around 28 C/82 F. Secondly, the water must be very hard and basic, 15+ degrees dH, pH 7.5-8.2. Finally, the water should be clean and essentially nitrate-free; 0 ammonia, 0 nitrite, and nitrate less than 20 mg/l. All these factors are critically important if you don't want to keep them in brackish water. Kept in brackish or marine conditions Mollies are exceptionally hardy, which perhaps highlights the reason why they are often said to be brackish rather than freshwater aquarium fish, despite being mostly freshwater fish in the wild. Ideally, you'd add about 6 g of marine salt mix per litre, for a specific gravity around SG 1.003.>
I do a water change and cleaning of the tank once a month. I am just wondering if this behavior is normal between mollies.
<Cheers, Neale.>

Black molly with bent spine 2/22/10
Hi, I had a 10 gallon with 1 guppy (male) , Mickey mouse platy and 2 Glowlight tetras.
<A small aquarium, and these wouldn't be my choices for fish. Or rather, while ten Glowlights would be fine in a 10 gallon tank, it's hard to justify keeping either Platies or Guppies in tanks this size. Both these species are active and somewhat aggressive sometimes, and I always recommend both species are kept in 15+ gallon systems because of this. In any event "2" Glowlight tetras really isn't an option, because they're social fish. Keep at least 6, and preferably more.>
I had it since October and no problems occurred. In the middle of January, I decided to get 5 new fishes since Petco was having a 5 for $5 sale. I got myself 2 male guppies, 2 gold barbs and one black molly.
<Now we're getting carried away! Black Mollies are a very poor choice for this aquarium.
Among other things, they need much more space than 10 gallons. The also need warmer water than most other fish. Platies prefer cooler water around 24 C, while Mollies need 28-30 C. Mollies also need hard, basic water, whereas Glowlights need soft, acidic water. Finally, Mollies usually do best kept in slightly saline conditions; if you add enough salt to make your Mollies healthy, you'll stress/kill your tetras and barbs.>
After acclimating them and observing them closely for a week, they were doing fine. The male guppies weren't fighting and none of them were nipping each other. At the end of January, I had to go back to school and I wanted to bring them back, but I thought it was too much hassle and left them home. The after one week into February, I got a call from my sister who was looking after them that the first guppy I had died from tail rot and the black molly had white spots on it and one of the guppy picking at the white stuff on the molly.
<Oh dear.>
Before I got back during the weekend, the guppy died from tail rot also. As soon I got back, I cleaned out the entire tank because I knew the white spots were ich and I read online that ich could be eliminated from cleaning out the tank completely.
<This is completely false. Nothing you do to "clean" this tank will prevent Finrot, Fungus or Ick. In this case I don't think Ick was to blame, since that comes into tanks with new fish, and would be apparent within a week or two of the last purchase of new fish. Finrot and Fungus are MUCH more probable because this tank is overstocked and contains fish that all need different living conditions. There's no way you could keep them all happy in this tank; therefore, at least some will get sick.>
After putting the fishes back in, the tank is running fine ever since the clean up which was about 2-3 weeks ago. As for the black molly, the lower half of the body was bent like a S along with the ich. Instead of putting it back together after cleaning the tank, I quarantined it. I also read that, if I constantly clean out the quarantine tank once or twice every week, the ich will go away in a matter of time because of the swimming form of ich will be thrown out.
<Where are you reading this stuff? It's all wrong. Utter, utter garbage.>
Previously, it wasn't eating much and swimming a lot, but now its a bit more active and come out to eat. However, it can only use the front fins to swim. What can I do about the bent spine and the ich and what caused it?
<Above all else, you need to read. Seriously. You need to learn about how to stock small tanks, and what to choose that will get along together without any changes to water chemistry, temperature or salinity.
Then you need to read about why fish get diseased, and how to diagnose those diseases
Above all else, you need to read about how to set up an aquarium, and how to maintain it
Thank you
<Cheers, Neale.>

Ask the WWM crew a question - Sick new momma Molly 2/18/10
We are new to fish keeping and have a reasonably new tank, set up on 26 Dec 9.
<Mollies are terrible choices for immature aquaria.>

It appears to have finished cycling as the test levels are coming in
great...Temp 25C, PH 6.4, Alk 60ppm, Hardness 110ppm, Nitrite 0ppm, Nitrate
12.5ppm and Ammonia 0.1mg/L.
<Not "great" at all, certainly not for Mollies. Let's recap. Mollies need hard, basic water, i.e., high alkalinity and high pH. You have neither.
Secondly, if you're foolhardy enough to keep them in freshwater, water quality must be absolutely perfect, 0 ammonia, 0 nitrite, and near-zero nitrate. Invariably, they are best kept in tanks with some salinity. 3-5 grammes of marine salt mix (not tonic/aquarium salt) per litre helps, though this of course limits the selection of freshwater fish you can keep alongside them. Put another way, if the water is brackish enough for Mollies to thrive, it will be too salty for the average freshwater fish. In short, Mollies are difficult fish. Every book ever written explains this, and the folks who buy them without realising their strict water chemistry needs are the people who haven't read anything about them. Start here:
Those results were taken on the evening of 16 Feb 10. When we have been taking the readings we have read the results independent of each other.
When we had a discrepancy in what we read, we took a median number if we couldn't agree.
The tank is 10 US gal and has about 1" of aquarium gravel on the bottom, three small 100% peat moss plant pots, one small terracotta plant pot and a 4" piece of PVC pipe on the bottom.
<10 US gallons isn't enough for Guppies, let alone Mollies.>
The tank also has a Banana plant, Wisteria, Water Sprite, Pennywort and a tiny blade-leafed plant. Some of the plant matter is planted in the rocks, some has rooted on the peat moss plant pots and some is floating.
<At least some of these will be killed by water saline enough for Mollies.>
Aquarium salt has been added to the tank over a period of time beginning about 6 weeks ago. We don't have a way of testing the salinity but estimate it probably has about only about 2tsp for the 10 US gal tank. I know this is a bit low.
<Yes, the wrong salt, and too little of it.
Aquarium salt is overpriced cooking salt. As I'm sure you remember from chemistry classes at school, sodium chloride has no impact on hardness, alkalinity, or pH. This is why you have an acidic pH and a low hardness, both things lethal to Mollies.>
We also realize that the peat moss plant pots have lowered the PH level however these were added about 2-3 weeks ago and the fish haven't appeared to have had a problem with it.
<Well, they're getting sick now. Don't use peat in any aquarium where hard, basic water is required.>
About two weeks ago and then again one week ago we added half a tablet of Jungle Correct PH to slowly bring the PH level up again. The fish did not appear to have a negative reaction to the peat moss or water conditions, in fact they seem to like nibbling at the surface of them, particularly the Cory.
<Corydoras are not compatible with Mollies. Besides the need for salinity, Mollies also need MUCH warmer water, around 28-30 C, and that is lethal to Corydoras in the long run. Corydoras prefer soft to moderately hard, not too basic water that has a low water temperature; aim for pH 6.5-7.5, around 10 degrees dH, and a temperature of no more than 24 C except in the case of Corydoras sterbai. Who recommended this insane selection of fish?
Did you do any reading at all? Also, Corydoras are SCHOOLING fish, so if you have just one Corydoras rather than five or more, then again, you've done no reading and inflicted your ignorance on this poor, terrified catfish.>
The environment is controlled by an immersible heater, HOB AquaTech 5-15 filter and a small air stone. The filter cartridge was changed on 16 Feb 10.
<Cartridges annoy me somewhat, because they invite less experienced aquarists to make silly mistakes. Do make sure you understand how filtration works, and don't replace more than 50% of the mature biological filter medium within a 6 week period.>
The tank had three Mollies (one female orange [Holly], one Dalmatian male[Mation] and the new momma who is a female black[Dolly]) and one Cory Catfish[Cody].
<Do understand fish couldn't give a rip about cute names. Animals generally don't want to be loved, they want to be cared for properly. This means reading up on their needs, and then planning accordingly.>
Two days ago (16 Feb 10) we noticed three black fry so we are assuming they came from our black Molly. The fry are currently a tad over 1/2" in length. There seems to be no problems between the fry and the adults.
Because of the new fry we did not do the water change that we had planned for 16 Feb 10. Instead we put a bit on pantyhose around the bottom of the filter and changed the filter cartridge. We also turned on the air stone to increase the oxygen content of the water.
Now the problem. We hadn't known she was pregnant prior to finding the fry but Momma seemed to be fine that day. She was fine yesterday as well, although her feces did, at one point, have a 3/8" strip of pink connected between two normal white feces she normally has. We only noticed the pink once. This morning (18 Feb 10) we were leaving early and just did a quick head-count. She appeared fine, just casually swimming around. When we returned home around 5pm I fed them. I have to confess that I can't remember for certainty if she came to eat when I fed them or not as I wasn't particularly watching her at meal time. Around 7pm she was behaving abnormally. She has no obviously physical signs of illness other appearing to be a bit curved. She is exhibiting symptoms of being unwell and/or stressed as she is hiding and rarely moving unless disturbed by something, i.e. another fish swimming close-by.
<Likely Shimmies, a classic reaction to poor environmental conditions.>
We have had the black molly and the Dalmatian for about three weeks and we have had the orange molly and the catfish for about 5 weeks. The tank finished cycling about three weeks ago and then we had a small spike(cycle) that took about 1-2 days to clear up when we added the latest two mollies [Dolly & Mation].
<Adding more Mollies when one is already sick!>
Not sure if there is a connection or not but the orange female Molly has been aggressive towards the male Dalmatian for the last couple of days.
She was like this about four weeks ago with another male Molly we had but since he died (not sure why but put it down to her picking on him) she has been non-aggressive. She has never been seen bothering the black Molly (new momma) at all. She just chases the male.
<The tank is about a third of the size it needs to be fore this species;
ergo, stress and aggression will be common. See here:
The fish are fed on TetraFin once a day. I don't think I am overfeeding as I feed them a circle about 3/8" in diameter and about 1-2 flakes thick each day. Since the fry arrived I have been pulverizing a portion of that amount for the little ones.
Please help us save our new Momma!
<Up to you. You're doing lots of things wrong and seem to have made no effort at all to read up on the needs of your fish. All I can do is tell you what Mollies and Corydoras require; it's up to you to provide those conditions.>
Thanking you in advance,
<Happy to help.>
<Cheers, Neale.>
re: Ask the WWM crew a question - Sick new momma Molly
Greetings Neale,
<Hello Lesley,>
Thank you for your prompt response.
<Always happy to help.>
I feel like I have been doing nothing but reading about fish since Christmas.
<Ah, I see. Does depend on *what* you've been reading. There is much misinformation on the Internet, which is why we recommend beginners have at least one tried-and-trusted book at their disposal.>
It is too early for me to tell how the black Molly is doing today as the light doesn't come on for another hour and with her being black, she is hard to see without the lights on.
Just a couple of points of clarification. We didn't start the tank with Mollies.
We didn't put the Mollies in until we had had the tank for about a month.
<I see. Still, I'd wait more than that before adding Mollies. Ironically, Mollies have been used in the past to cycle marine and brackish water tanks. They do very well in marine conditions, and sail through the cycling process better than (more expensive) reef fish. It's only in freshwater tanks that they are incredibly delicate. While there's argument over whether they absolutely *must have* brackish rather than freshwater conditions, all fishkeeping writers agree they're often *easier* to keep in brackish water. Few experienced keepers recommend them for beginners or even general community tanks.>
I have learnt that was probably too soon to have a cycled tank but unfortunately the generic pet store where we started at misinformed us that 3-4 weeks is all we needed.
<I see. Again, having a book helps.>
We didn't put new Mollies into a tank with sick fish. After the previous Mollie died we made sure that the remaining orange female Molly and the Cory were still looking healthy and waited a couple of weeks before buying her a pair of tank mates.
I have read your article on stocking the tank. Unfortunately I didn't see it before we started. I had read many articles speaking of "one inch of fish per one gallon of water" and that was what we were using as our guide.
<This rule is hopeless and misleading. Think about an extreme example. A Great White Shark has about the same number of inches as 120 Neon Tetras.
So by the "inch per gallon" rule they'd need the same size aquarium. But do you suppose that's true? Of course not. The "inch per gallon" rule makes some sense where Neon-sized fish are concerned, and assumes the tank is above a certain size suitable for keeping fish generally; i.e., it doesn't mean you can keep a 1-inch fish in 1 gallon of water. Frankly, I'd BAN this rule, because it seems to create more misunderstandings than it solves.
Much better to find out how much space a fish needs from an aquarium book, and then stock your tank accordingly. So if you're keeping Peppered Corydoras for example, you'd read up that a group of six need around 15-20 gallons, and keep a group that size in a tank that size. If you needed to add 3 this month and 3 next month, that's fine, but the point is you'd have a sensible goal to work towards.>
We also quickly learnt that a generic pet store (or at least ours) has no clue about fish.
<Unfortunately all too common. Again, a book helps.>
They told us we only needed to wait 24 hours before adding fish...wrong!
We have migrated to using a fish specific store called Fintasics and had been trusting their recommendations for both fish and plants. I can see now that we are going to do more of our own research and be less dependent on the shop.
<Yes. As I point out repeatedly, you wouldn't trust someone selling you a house, a car, or even a new pair of trousers this way. By all means listen to their advice, but balance it against your own research. There are numerous good books for beginners.>
We have both been reading every day, learning more and more but we have a long way to go. That article on stocking the tank is just one example of what I wish we'd found before having issues instead of trying to close the barn door after the damage is done.
We do have a second 10gal tank that we have just started trying to cycle.
We were planning on using it for growing plants (since our fish seem to like eating the ones we have) and also as a quarantine tank if we ever got any new fish.
<Mollies will certainly eat soft plants given the chance. I recommend Indian Fern for this, because it grows so fast it'll keep up. Plus, in growing fast it uses up nitrate and minimises algae problems. Best of all, it tolerates slightly brackish water very well (around SG 1.003) making it a great addition to the Molly aquarium.>
Short of killing the fish deliberately, do you have any suggestions for us?
<If you can, convert one tank to a slightly brackish one, so that it's ideal for Mollies. SG 1.003 is equivalent to 6 grammes of marine salt mix per litre, so a box of Instant Ocean or whatever will last for ages. This is a cheap way to ensure optimal water chemistry, and the salt also minimises nitrate and nitrite toxicity, helping significantly where Mollies are concerned. Make the other tank a soft water one, and use that for Corydoras and perhaps a few soft water schooling fish, like a school of Neons. I wouldn't keep Danios in 10 gallons, but Neons are fine, and they like the same fairly cool conditions as most Corydoras.>
I'd rather not just kill them off and I don't know of any place to adopt them out to. The store doesn't take them back and I am unaware of any fish clubs in the area.
<Well, you've pretty well eliminated the possibilities!>
If possible I'd like to keep them as I have grown fond of them all but ultimately we need to do what is best for the fish.
As for our black Molly, if I am understanding correctly there is nothing we can do for her right now except keep our fingers crossed and try to improve her tank conditions. Is that correct?
<Pretty much. The "Shimmies" is a neurological disorder, and other than improving conditions, there's nothing specific aquarists can do.>
How drastically can we improve her tank conditions in a short time frame, i.e. 24 hours before the shock of the change outweighs the benefits of the new conditions?
<If the Corydoras are moved to another tank, you can start to switch over to slightly brackish (SG 1.003, as described above) at once. This will not stress either the filter or the fish if done correctly. Do a 20-25% water change now, adding SG 1.003 water (i.e., a bucket that has 6 grammes marine salt mix added per litre *in the bucket not the tank*). Do the same a week from now, and after a month you should have adjusted the salinity safely without any problems. The Corydoras will put up with perhaps one water change like this, but their tolerance for brackish water is low, and long term, they shouldn't be kept alongside Mollies. On the other hand, the slightly brackish conditions are ideal for a host of other fish, including Guppies, Platies, and other livebearers. There are some nice species like Wrestling Halfbeaks and Humpbacked Limia that are, if anything, hardier than fancy Livebearers, and lots of fun to keep. So the use of salt, while restrictive in some ways, opens lots of doors, too.>
Help again, please,
<Good luck, Neale.>
Re: Ask the WWM crew a question - Sick new momma Molly -- 02/19/10

Hi again Neale,
Well the lights came on and she is still alive but looks like she is worsening.
She was laying curled at the bottom half beneath a banana plant. The Dalmatian Mollie (male) was picking at her (nudging or nipping her, couldn't tell).
<Likely aggression. Male Mollies are not nice to the females.>
We decided to risk moving her. I know the stress of moving her is very bad but leaving her to be constantly bothered by the male I figure was bad as well so it seemed like a case of damned if we do and damned if we don't.
We put her in a 1 gal bowl with about 3 litres of water. We took the water from the tank she was in and added a bit (basically a pinch) of aquarium salt to it (the only salt we have on hand right now). We also put in a heater and a small air stone as well as a minute amount of food, some rocks (from her old tank) and a bit of floating plant matter.
<Not going to help. At minimum, you need a mature filter in an aquarium.
Air stones won't remove the need for filtration, and 1 gallon of water will turn bad really quickly.>
I don't know if we did the right thing or the wrong thing.
I guess time will tell.
<I'm afraid I can tell you now.>
If she survives the day our plan is to change the bowl water about 10% a day since we have no filter in the bowl.
<Indeed. You'll need to change at least 50% daily, and that assumes you're keeping the water chemistry steady. If the water is soft and acidic, this won't be the case, because soft water is inherently unstable in a way hard water isn't. And as I've stated before, salt has no impact on this either way.>
We are planning on using water from her old tank as the replacement water.
<Hmm... hardly likely to help if conditions in the mature aquarium are not ideal (and they're not).>
We didn't put her in the new 10gal tank since it is only a couple of days old at the moment and is no where near ready for livestock.
<I'd sooner cycle a 10 gallon tank with brackish water and mollies than leave them in a cycled soft-water aquarium. No debate. None. Zip. Nada.
Overnight, cooking salt at 6 grammes per litre will do, and then tomorrow you can go buy proper marine salt mix. Simple as that.>
Thank you for all your help,
Keeping our fingers crossed,
<Cheers, Neale.>

Molly Worries... hlth. mostly 2/15/10
I have searched your site but cant find a similar problem. We have a 150 l tank with 4 mollies (+4 babies approx 2 weeks old), a Plec, and 4 small silver sharks. Yesterday we added 3 zebra Danios, and 11 small cardinal tetra.
<You do realise Mollies, Danios, and Cardinal tetras all require completely different water conditions? It would be difficult for anyone to keep all three together for long. Just to clarify, Mollies need warm (28 degree C) water with a high hardness and pH (at least 15+ degrees dH, pH 7.5-8).
Although not 100% essential, Mollies are infinitely easier to keep in slightly brackish water, i.e., with about 3-5 grammes marine salt mix added per litre of water. This is especially the case if you have soft rather than rock hard water. Danios by contrast are intolerant of salt. They need quite cool water, around 22 C is ideal. Cardinals are even less tolerant of salt, and actually need soft, not hard, water to do well; pH 6.5-7, 5-10 degrees dH. They also need warm water, like Mollies, around 28 C. So, any tank suited to any one of these fish would be -- at best -- stressful to the others.>
We have been super careful with water and have just re tested for Ammonia, as well as nitrates. nitrites, hardness and PH. The only changes are that Nitrate has increased from 25 to approx 50.
<Hard to know what you mean by "super careful" in this instance, because these fish all have such different requirements. Who suggested you mix Cardinals with Mollies? Did you read up on how Danios prefer quite cool
water? Or that Cardinals need soft water, while Mollies need hard water, preferably with some marine salt mix added? I'm not trying to be facetious here; I'm merely stating that this is an incredibly poor combination of fish.>
Our orange male molly has for the last day been almost sat on top of the filter. He is not gasping for air and is just hovering there, I think he is resting on the filter but it is hard to tell as its a corner tank and he's right in the corner. He came out to feed then went straight back to the same place. Other fish are swimming right past him and he is not
flinching. Is he sick?
<Could well be. Mollies are quick to get sick in poor water quality (non-zero levels of ammonia and nitrite). They are also extremely sensitive to nitrate, and if kept in freshwater -- as opposed to brackish water -- nitrates MUST be below 20 mg/l. They are easily "chilled" as well. In short, they're difficult fish to wedge into community tanks, though extremely hardy and easy to keep if their needs are accommodated. Classic symptoms are Finrot, Fungus, and something called "the Shimmies" which is a bit like treading water, often rocking from side to side as well.>
All the forums seem to suggest it is a sign of giving birth but he's definitely got the gonopodium, although not as pronounced as the other males.
<Useless advice, on the part of whatever forums you visited.>
<Cheers, Neale.>
Re: Molly Worries 2/15/10
Thanks for the quick response, and sorry if it seems like we have been silly in our choices.
<Happy to help.>
We took advice from a shop called World of Fishes which according to their website and posters all over their shop were voted in the top 15 aquatic stores in the UK by practical fishkeeping magazine!
<It's important to balance the overall quality of a store with the need for shoppers to use their own research.>
We've had the mollies for approx 2 months now with no obvious problems.
When I say careful I mean we have set it up following advice and regularly test (twice a week) to see any changes. Tank has live plants in it and a sand substrate. temp is 25/26 C, Ammonia = 0, Nitrate usually 25 but increased to between 25-50 today (test doesn't go any more accurate than that), Nitrite =0, hardiness - GH - between 8-10, KH= 3 and PH is 7.2.
<Water isn't hard enough or basic enough for Mollies.>

I told the man in the shop what fish we already had, and enquired on whether the fish we were looking at (Danios and cardinals) were suitable and he said yes. I though neon tetras were more suitable than cardinals from my reading but he said they were no different.
<Neons and Cardinals are very different in requirements. Neons prefer rather cool water, around 22-24 C, and as such, go great with other "low end" tropical fish such as Danios and Corydoras. Cardinals on the other hand are "hothouse flowers" and won't do well below 26 C, and really need to be kept at a more toasty warm 28 C for best results.>
It seems odd for them to suggest cardinal tetras as the water in our area is hard.
<Neither Cardinals nor Neons do well in hard water, and I doubt your specimens will last the full 4-5 years they should last.>
We did a 10% water change yesterday, do you think it would be a good idea to do another one?
<By all means do daily 10% water changes until you get the nitrate level below 20 mg/l, which you will need if the Molly is reacting to high nitrate levels (and it probably is). Better yet, understand the needs of the fishes you have, return the ones you can't keep, and choose species that all share the same requirements in terms of temperature, water chemistry, and where relevant, saltiness.>
thanks Claire
<Cheers, Neale.>

Black molly, hlth..... env., no reading, U.S. invades yet another sovereign nation, discovers murdering other countries citizens doesn't bring freedom to anyone... 2/9/10
I have a female molly who recently started shaking, she stays in one spot and just shimmies her body back and forth. When I was observing her I noticed her belly was a little square, and she has some white spots on her belly. I have only had my tank for just over a week, its a ten gallon tank with 3 black mollies, 3 red wag platy, and a male Betta.. I dont think the spots are ich because they dont look like salt residue on her, just a coloration difference. she also has one white spot where the babies would come out of. none of my other fish have any problems, I dont know what's wrong with her? oh, and she's been doing it for just over 48 hrs. could this just be a reaction from pregnancy?
<It's unlikely she's sick because she's pregnant (or been pregnant).
Mollies are sensitive fish, and need good conditions. Your tank is far too small, and I'd bet some money she's in freshwater rather than brackish water conditions. While brackish water conditions aren't 100% essential, they do make keeping Mollies so much easier. Use marine salt mix (like you'd use in a reef tank, e.g., Instant Ocean) at a dose of 3-5 grammes per litre. Your Platies will be fine with this, but the Betta will need to be rehomed. Bettas and Mollies aren't compatible. One problem with Mollies is they need very warm water, around 28 C, and this can stress the Platies, so ensure water quality and water circulation are both good. Without these fixes, this fish will die. Do read here:
As always, read about your fish prior to purchase. Cheers, Neale.>

Help with black molly disease... more of the same... 2/9/10
I have a small 10 gallon community tank with 3 male guppies, 2 zebra Danios, 3 neon tetras, and a black molly.
<Insanely overstocked with the wrong fish.

Ten Neons would be fine in here. Zebra Danios have no place in a tank this small, and male Guppies really shouldn't be in here either. The Molly shouldn't be within six feet of a 10 gallon tank!>
Well all of them are doing great except for the black molly we have had this tank and the fish for a year and they where all doing great, but the black molly for the last 2-3 months has been getting sick a lot.
<Not uncommon when people throw Mollies into tanks they can't survive in.>
We treat it with Maracide or this other med Quick cure. It usually gets rid of it for a day to a week but then it just gets ich again.
<As you'd expect. It's the environment and lack of proper care causing the problems.>
Well this time I checked on it and it has ich terribly, has I think Popeye and its mouth and eyes are swelled shut. I feel really bad for it and I dont think that the other meds will help it this time and I was wondering if it needs some special tank environments or anything.
<The book you read about aquarium fish *before* buying Mollies didn't mention anything about hard water, high temperature, and a preference for brackish water?>
I separated it into its own little 1 gallon tank to treat it in,
<Death trap; a 1 gallon tank isn't anything but a wet coffin. Seriously. If it was sick in a 10 gallon tank, what made you think reducing that environment by 90% was going to improve things?>
it will just be in there untill it gets treated and is in good health again. We just treated it with the quick cure and I was wondering if I could do anything for it.
<Yes, lots. To start with, keep it in an aquarium suited to its need. Do read here:
If transferred to a spacious (20 gallon) brackish water aquarium with around 5 grammes of marine salt mix added per litre of water, and then treated against Finrot and Fungus, this fish should recover. If not, it's doomed. Let's be clear here: it the decisions you made that led to this problem, not the fish, and not mystery diseases. Up to you to make such decisions as will reverse the situation.>
(I put some pictures of it but my camera doesn't want to focus on the fish so they are blurry)
<Indeed. And do note that we specifically ask for small (in size) images around the 500 KB range; bigger than that clogs up our e-mail system, bouncing back other people's messages. Cheers, Neale.>

Re: Help with black molly disease... & Now Brachydanio as well 2/9/10
O I feel really bad now. I think the one type of fish are zebra Danios they have dots in a form of a line, and are about the size of the guppies.
<Danio rerio, a common enough species. Gets to about 5 or 6 cm in length, and it's really a hyperactive species that needs not less than 60 cm/24 inches of tank length to swim about in. In smaller tanks its apt to behave abnormally, either becoming shy, jumpy, or sometimes aggressive.>
I just looked up zebra Danios and the one fish is one but the other I dont really know what it is it kind of looks like one but doesn't at the same time.
<Quite variable. If these were sold as "Danios" they're almost certainly Danio rerio, the Zebra Danio.>
The only fish that isn't doing great is the molly and it was doing great before the last month.
<As happens. This species isn't easy to keep in freshwater aquaria, and really isn't a beginner's fish.>
I use to have guppies in this tank we would buy a male and 2-3 females then breed them as the fish for the tank. After doing this for 4-5 years my mom got sick of just guppies and just went to the pet store and bought random
some fish while I was at school.
<I see.>
She asked the petstore she bought them from and they were all in the same tank there. She asked the people there what they were and what their care needs where and the guy said that they all needed the same needs and then
he labeled them the wrong fish and sold them to my mom.
<This sort of thing happens quite a lot, unfortunately. While I sympathise, and certainly understand, I can't offer any instant cures.>
We currently dont have the room for a 20 gallon tank or even another 10 gallon. And mom isn't willing to buy a tank anyways she thinks that if we just treat it again that it will be fine.
<She's wrong.>
Would a 3 gallon tank be ok for it?
<Not really, no.>
I have a 3 gallon tank that my female Betta was in untill I got it a 10 gallon tank. I might be able to find a spot for the 3 gallon one. I already have some fish tank sea salt for the water because I have brine shrimp in a little container, and I have extra salt.
<Tonic/aquarium salt is not quite as good as proper marine salt mix (Instant Ocean, Reef Crystals, etc) but will do in a pinch.>
Also is there anything I could do for the other fish without having to move them into a different tank?
<Not really, no. Maintaining in brackish water AND treating for Finrot/Fungus will help, but better conditions will be needed. Mollies aren't really community fish, and that has to be borne in mind.>
Like I said my mom isn't willing to go buy another tank or anything.
Thanks for your time
<Cheers, Neale.>

Black molly (male) with distended belly -- 02/02/10
Hi WWM Crew,
I have a black male molly in a tank at work that has an enormously distended belly (or chest, perhaps, depending on how you look at it).
<Do review the basic needs of Mollies. They tend not to do well in freshwater tanks. Yes, sometimes they do okay. But just as often they don't. In particular, when maintained in freshwater tanks they are very sensitive to poor water quality, including high nitrate concentrations.
In short, Mollies are a bad choice for the ordinary freshwater community aquarium.>
Some background:
There was originally a Pleco in this tank that died about 6 weeks back. A coworker asked that I bring in some of my numerous mollies on a Friday morning. Unbeknownst to me, the tank had not been properly cleaned since the pleco's death (I don't tend this tank - my coworkers do), and by Monday when we came back to work the mollies had a terrible fungal infection. My coworkers had not added salt and what not to the tank yet, so I quickly did a large water change (about 50%) and added the cichlid mix found on your site (which I also add to my tank at home).
<The Rift Valley salt mix should help, but there are some other issues.
Let's put aside salinity for the moment. Mollies in freshwater tanks need a high temperature, around 28 C (82 F). They need very hard water, 15+ degrees dH. They need high carbonate hardness, 5+ degrees KH. They need a high pH, 7.5-8. Water quality has to be superb: 0 ammonia, 0 nitrite, and nitrate less than 20 mg/l. All these things are either difficult to achieve in a freshwater community tank, or incompatible with most community fish.
The temperature for example is far higher than Neons, Danios and Corydoras will appreciate, since they're happiest around 22 C (72 F).>
My coworkers continued to do water changes until the water quality came back down to a good level, and the growths cleared up. My coworker treated with API anti-fungal as a precaution.
About a week ago, I noticed that the male's belly was growing, and I told my coworkers to continue changing the water by about 10% each day but to omit baking soda in the cichlid mix thinking that the hardness may have been off (as per a similar FAQ found on the site). It tested at around 11.5 - a little low as I understand it.
<For Mollies, yes, 11.5 degrees dH is too low.>

We've now gone through multiple water changes and the water quality is pristine - hardness is up around 14 dH, pH is at 8, nitrates, nitrites, and ammonia are all stable, and the temperature is at 81F.
<What do you mean by "stable"? Needs to be zero for ammonia and nitrite.>
The male molly's belly is even larger than ever though.
<I see.>
I haven't seen any signs of stringy white feces that would point to parasites.
<The white stringy faeces are particular to Hexamita infections, rather than infections generally, so the lack thereof doesn't rule anything in or out.>
Other than the pregnant belly look that he's got going, he looks healthy and is behaving as I'd expect.
<Three obvious things. One is simply constipation. These are herbivores, and a lack of fibre can cause problems. Green foods like cooked peas and spinach, plus "shelly" live foods like daphnia and brine shrimp, can help.
The second potential issue is intestinal worms, in which case an anthelminthic drug will be required, such as Praziquantel. The final issue is that this Molly, like many others, just isn't going to do well in a freshwater aquarium. I know I repeat this again and again, and there are lots of people out there who maintain Mollies in freshwater tanks, but honestly, it's just not a reliable approach.>
As always, many thanks.
<Cheers, Neale.>

Dalmatian molly swimming on side 1/12/10
I bought two Dalmatian mollies this afternoon and one of them is now acting strange. It seemed okay when I put him in the tank, but after an hour he took up a place under the filter and wouldn't move.
<Almost always, Mollies react this way when moved into poor water conditions. Do remember that Mollies are very fussy in their requirements.
At minimum they need basic (pH 7.5-8) water that is very hard (15+ degrees dH) and very warm (28-30 degrees C). Many experienced aquarists, myself included, would further insist on the addition of marine salt mix to the water as well. This raises the salinity AND the carbonate hardness. About 3 grammes per litre usually does the trick, though you can add more if you want to.>
When I fed the fish, he didn't show any interest (to be expected the first day) but the other one ate just fine. An hour ago I noticed he had moved behind a plant in the back and was tilting to the side, and after readjusting would flip to the other side. He even flipped completely over twice. I immediately pulled him out of the tank to my small extra/sick tank. He still seems to be having trouble swimming upright. When I went to catch him in the net he swam away normally. Could he have Whirling disease?
Or maybe I transported him home wrong?
<More likely he's unhappy in the tank you have him in.>

I always take a small portable tank/fish carrier, and I buy a container of Chlorine free/Oxygenated water, at about 70 degrees, to put in the tank and then slide the fish out of the bag into the tank. We have to drive over an hour to get to a fish store so I always try to transport them this way so they won't be in the bag too long. I use a small heater to adjust the temperature slowly when I get home, and then add them to my existing tank.
Maybe this stresses them out more?
<Don't think this is the issue.>
I have a 30 gallon tank with 7 Neons, one Dalmatian molly (plus the two I bought today), one small Peckoltia, and 7 small Danios/Glofish mix.
<Neons and Danios both appreciate fairly cool water, around 22-25 C (72-77 F). This would be far too cold for Mollies. You cannot keep these three species together and expect them all to be healthy. Please do READ about what fish need PRIOR to purchase.>
My ammonia is at 0, my nitrites are at 0, and the nitrate is at 10. I do weekly 20% water changes and keep the temp at 72-73.
<Too cold.>
I am afraid I have brought home a diseased fish, but he appears to be perfectly healthy, no nipped fins or ich spots, except this problem.
<Problem environmental.>

The other fish was in the same tank at the store, and all the other fish in the tank were clean and healthy. Please let me know soon if it is whirling or something else. I'm not sure he will survive the night and if he dies I may take the other fish back to the store. Should I take it out and place it in my sick tank with the other fish now as a precaution? And if it is whirling or something else, can I treat it? Thanks for the help, Cristina.
<Do read here:
Cheers, Neale.>

Mollie with distended bowel still moving though not much 11/20/09
Hi, fed my fish as usual this morning went past the tank a few hours late to discover m big molly upside down in the plants with a very distended bowel have had all the fish in the tank for around three years with no problems except for 2 silver sharks that kept jump out of the tank to their eventual demise...I am really worried about my molly what if anything can I do????
<Hello Ren. Mollies are sensitive fish that need very specific conditions to do well. They need warm (28+ C) water with a high hardness (15+ degrees dH) and a basic pH (7.5-8.2). The addition of marine salt mix, while not absolutely essential, is usually a very good idea; 3-9 grammes/litre works well. They need quite big tanks to do well, nothing less than 90 litres, and realistically 110 litres or more for the bigger Sailfin Molly species. Water quality must be excellent: 0 ammonia, 0 nitrite, and nitrate levels below 20 mg/l. Do read here:
You haven't provided me with any useful data here, so I can't offer any better advice than this. Read through what's needed, and if you want to discuss further, write back. While I suspect this fish is doomed, it's as well to know how to keep Mollies so this doesn't happen again. Cheers, Neale.>
Re: Mollie with distended bowel still moving though not much 11/20/09

Thank you Neale for you advise, unfortunately my molly did die, but thank you for the extra info.
<Happy to help.>
My fish are in a 90 litre tank, water temp is around 26-27 C. At the moment the pH is around 6.6 which isn't to good I now I have made adjustments though,
<Far too low for Mollies, and almost certainly the problem. An acidic pH implies soft water, and soft water is lethal to Mollies. Don't change the pH without changing the hardness. This is a common mistake people make. They buy " pH up" and "pH down" products, thinking these will make everything okay. They do not. These products are intended to be used as buffers -- chemicals that stabilise pH -- alongside changes in water chemistry. In the case of Mollies, hardening the water by adding a Rift Valley salt mix is cheaper, safer, and better.
Alternatively, convert the aquarium to a brackish water aquarium at around SG 1.005; if you use marine salt mix to do this at 9 grammes/litre, the pH and hardness will be taken care of automatically.
in the tank there are the mollies, and clown loaches and leopard catfish.
<Neither of these tolerate brackish water, and both will do better on soft water than hard water. As should be clear: Mollies cannot be added to soft water communities, and are best kept with species that prefer (or at least tolerate) similar conditions.>
The mollies and loaches are quite big now had them since the were very small guys. Would it still be suitable to add the marine salt with the other types
of fish in the tank as well??
thanks again
<Cheers, Neale.>
Re: Mollie with distended bowel still moving though not much 11/20/09

Hi Again
I know this will sound very amateurish but what is hard water?
<This is in the article I mentioned, here:
Hard water is water with a lot of dissolved minerals in it. There are two types of hardness aquarists measure: General Hardness (degrees dH) and Carbonate Hardness (and degrees KH). Each is important, but measuring general hardness alone is usually good enough if you also know that the pH stays around 7.5 from week to week. Typically, this is the kind of water that furs up kettles and is good for brewing beer. If you are using a washing machine, you need to add extra washing powder because hard water doesn't lather easily. But for fishkeeping, it is ideal for a wide range of fish, including livebearers, Goldfish, and many (though not all) cichlids. Because marine salt mix contains chemicals that harden water and raise pH, brackish water aquaria are hard water aquaria automatically, and so are ideal tanks for keeping Mollies. Cheers, Neale.>

Worried for my fish. Molly-Neon mis-mix, no reading, full moon stuff... 11/18/09
I have one Dalmatian Molly, one gold molly and 4 neon tetras together in a large tank, it has plenty of plants.
<Do understand Neons and Mollies are not compatible. Neons
need cool (around 22-25 C) water that is soft to moderately hard, and not too basic (5-15 degrees dH, pH 6.5-7.5). Mollies by contrast need much warmer water (around 28 C) and the water must be very hard (15+ degrees dH) and very basic (pH 7.5-8). They almost always do better when some marine salt mix is added, at a dose of between 3-9 grammes per litre depending on the tankmates and plants. All of this will be quoted in aquarium books, which is why we recommend you read a book before buying any fish.>
I have recently found out that both my mollies are male (thank goodness) My concern is, for a few weeks now my gold molly has been getting fatter very ball like and can no longer swim, he sits in one spot all the time on the bottom of the tank, my Dalmatian molly appears to be fretting for the gold as he is always going over to him and trying to lift him off the bottom of the tank, he is continuously trying to push him up, and when he gets the gold up so far the gold just sinks straight to the bottom of the tank again,
<He is not "fretting" but being aggressive.>
His breathing has become more erratic and I've noticed his fins are getting faster in movement but he's still not getting anywhere. He has also stopped eating now and I'm worried he is going to starve as it has been a few days.
<What are the water conditions? As stated above, Mollies need very specific conditions to do well.>
I have medicated the tank with a multi purpose treatment but it has had no affect on him.
<Useless approach. Diagnose the problem, then treat. Imagine if your doctor couldn't be bothered to check your symptoms, and just gave you the first pot of pills he pulled from a drawer!>
I separated him from the others but he looked panicky and was constantly pushing up against the side, while he was in the other tank I noticed his anus was very white and looked like it was protruding out of his body like a hemorrhoid.
<Is not this.>
I'm concerned for my other fish as my Dalmatian molly is more active then usual in what looks like a concerned manner. and one of the Neons seams to be becoming rounder in the tummy and becoming slackish in its movements.
<Check water quality and water chemistry. For both species, 0 ammonia and 0 nitrite are critical. But since Neons and Mollies need completely different water chemistry, it's unlikely (i.e., impossible) to keep both species 100% successfully in the same aquarium.>
Id appreciate any advice you could give me as I don't want to loose any of my fish.
<I'm afraid they're doomed. You've thrown two non-compatible species together, and without giving me any actual data in terms of water quality, water chemistry, or temperature, I have no idea what precisely is going on here.>
I have looked all over websites trying to find an answer but nothing that I can find displays any of his symptoms together.
<These sound like generic "get me out of here" symptoms exhibited by fish being maintained in a poor (or the wrong) environment.>
<Cheers, Neale.>
Re: worried for my fish, Molly hlth. 11/18/09

Thank you for your reply.
<You're welcome.>
I have tested the ph in my tank, and it is reading at 7.6, the temperature is 28 C all of what you have described as good conditions for the Mollies,
but I have not added any salt to the water.
<Ah... this isn't essential, but it really does make a huge difference.>
I have these 6 fish in the same tank for the past 6 months and have had no problems with them till now.
<As is the nature of things.>
The Neon appears to have gotten over his swollen belly and is back zipping around the tank like he always has.
Unfortunately the pot belly molly has gotten worse today an is now lying on his side, I do not expect him to see out the week. he is non responsive to me when I approach the tank.
<As I say, Mollies just aren't reliable choices for aquaria where marine salt mix isn't added. I don't recommend people keep them that way.>
My Dalmatian molly is still trying to lift him off the bottom but not as much as before, he seems to have gotten attached to his reflection in the side of the tank and has been fiercely chasing his image back and forth across that side.
<Again, this "attachment" is aggression. Male Mollies are intolerant of one another.>
I had done some reading prior to getting the fish, as I have had Neons in the past and wanted them again, but I also wanted something else to go with them.
<Tricky things Neons. I think they're good choices for fish that also like coolish conditions, e.g., Danios and Corydoras. Platies are the livebearer of choice, being very happy at slightly cool conditions. Swordtails also do well in cool conditions, but they are a bit more aggressive (and bigger).
Guppies and Mollies need much warmer water though, and Mollies are fussier about water quality and water chemistry. Beautiful fish, yes, but not easy to keep.>
When I when into my pet shop to get the Neons I didn't ask if they were compatible with the mollies as they were already in the tank together there, I assumed they at the store new what they were doing and just asked for what was there.
<Ah, I see.>
I will however be returning to my pet shop to inform them that they do not belong in the same tank together.
<Should be interesting to hear what they say. As mentioned, not everyone keeps Mollies in slightly brackish water, but every aquarium writer agrees that they are often easier kept thus, and many miscellaneous problems just don't occur when Mollies are kept this way.>
Thank you once again for your advice, and I will be setting up a second tank right away to separate the two species.
<Certainly one solution. There are lots of fish that tolerate slightly salty water, including Guppies, Glassfish, Halfbeaks, various Gobies, and even things like Shrimps and Nerite Snails. Numerous plants will tolerate slightly salty conditions too (do read WWM re: brackish water aquaria for more).>
I do hope that by doing this I can save all there lives, Including my Pot Belly.
<I hope so too.>
<Cheers, Neale.>
Re: worried for my fish
Thank you once again for your hasty reply.
<Happy to help.>
Unfortunately after I sent my last email, I checked on my molly and he had died.
<Not surprised, really. Sad anyway.>
When I removed him from the tank his belly was extremely swollen but I could not find any marks on his body and his fins were still in good condition, I believe he may have just had SBD.
<Ah, now, there's no such thing as "Swim Bladder Disorder". This idea is a vague, arm-waving thing aquarists mention when they have no idea why their fish died. Putting aside constipation, the usual reason fish swell up is because of internal bacterial infections. These are caused by general environmental shortcomings. In the case of Mollies, this can very easily be water that is too soft, too cold, and, as I've said, insufficiently salty.
This is the thing with Mollies, they aren't reliable in freshwater aquaria.
We can talk about this all day, but it's still the bottom line: Mollies will sometimes die from stress-related bacterial infections when maintained in freshwater aquaria. The mystery is that Mollies do just fine in the wild living in freshwater rivers. So they don't need salty water in the wild.
There's something about aquaria, possibly nitrogenous wastes, that makes salt beneficial (salt detoxifies nitrite and nitrate).>
My Dalmatian Molly has become more aggressive towards his reflection, is there something I can do to calm him down?
<Castration. Serious, this is what male Mollies do. In the wild male Mollies spend all their time shooing off any male that gets close, so they can monopolise access to the females.>
It is rather funny to watch but I don't want him to get stressed.
<He'll be fine.>
Should I also put a female molly in with him, as He is rather large and dominant I don't want him attacking any other males I get.
<He will pester the female.>
As I said before I only had them in the same tank as the Neons because that is how they had them in the aquarium store.
<And as I said before, you need to read up on a fish before you buy it.>
I when back into the store this morning and asked them what there opinion was of having the 2 species in the same tank, (they have now added cardinals to the same tank making it three species)
The man told me that they hadn't had any problems with them and that they understood that Mollies are very hardy and have the ability to adjust themselves to completely fresh water.
<Note that pet stores keep their fish for a few weeks... they don't care what happens once the fish is sold.>
After explaining to them that I had been informed they need a little salt to do well, I was told it didn't really matter to them as they don't keep them for very long as the Mollies sell very quickly and after they leave the store its not there problem what happens to the fish.
<Precisely so.>
With this, I left the store. And am now looking for a new aquarium shop.
<Hmm... wouldn't be too hard on them, but as I say, you buy fish after you know what they need.>
The neon that had been getting fatter, Is now not so fat. and looks much happier now they are in there own tank. Once again thank you for replying.
I am definitely looking at buying your books so I am not bothering you with all my questions.
<We do have a page of recommended books for beginners.
Not sure what the selection is like in the Land of Oz, but I'd hope your public library at least will have a few useful tomes.>
Re Pot Belly Molly... Really worried... mixed w/ Neon Tetras... 11/18/09
I have one Dalmatian Molly, one Pot Belly Molly and 4 Neon Tetras together in a 20 gallon tank, with lots of live Plants..
I have recently found out that both of my mollies are male (thank goodness).
<Hmm... females are actually much easier to keep in groups, especially virgin females which won't breed and don't fight.>
My concern is, for a few weeks now my Pot Belly Molly has been getting fatter, very ball like and can no longer swim, he sits in one spot all the time on the bottom of the tank,
<Likely something like "The Shimmies" -- a neurological issue brought along by inappropriate maintenance. Mollies are very sensitive to nitrate (anything above 20 mg/l is toxic under freshwater conditions). They are also sensitive to chilling (anything below 28 C is risky). Usually, Mollies are most reliably kept in tanks with a little marine salt mix added to raise the pH, raise the carbonate hardness, and raise the salinity. While not 100% necessary, for non-expert fishkeepers the use of marine salt mix is HIGHLY recommended.>
my Dalmatian Molly appears to be fretting for the Pot Belly as he is always going over to him and trying to lift him off the bottom of the tank, he is continuously trying to push him up, and when he gets the Pot Belly up so far the Pot Belly just sinks straight to the bottom of the tank again.
<He is being aggressive.>
His breathing has become more erratic and I've noticed his fins are getting faster in movement but he's still not getting anywhere.
<Indeed not.>
He has also stopped eating now and I'm worried he is going to starve as it has been a few days.
<Likely so.>
I have medicated the tank with a multi purpose treatment but it has had no affect on him.
<Won't. A useless approach for the reasons I mentioned last time you wrote with the same message.>
I separated him from the others but he looked panicky and was constantly pushing up against the side, while he was in the other tank I noticed his anus was very white and looked like it was protruding out of his body like a hemorrhoid.
<Not this.>
I'm concerned for my other fish as my Dalmatian molly is more active then usual in what looks like a concerned manner. and one of the Neons seems to be becoming rounder in the tummy and becoming slow in its movements.
<Neons need specific conditions completely different to those of Mollies; temperature, hardness, salinity, pH -- all different.>
Id appreciate any advice you could give me as I don't want to loose any of my fish.
I have looked all over websites trying to find an answer but nothing that I can find displays any of his symptoms together.
Any help you could give me would be much appreciated. Thank you.
<Do read up on the requirements of fish *prior* to purchase. This Molly likely doomed, but transferring it to a clean, well-run, slightly brackish aquarium may help. Cheers, Neale.>

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