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FAQs on the Molly Environmental Disease: <Principal cause of troubles>

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

Related FAQs: Mollies 1, Mollies 2, Molly Identification FAQs, Molly Behavior FAQs, Molly Compatibility FAQs, Molly Selection FAQs, Molly System FAQs,
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,

All Molly species live in hard, alkaline water; most with a good amount of saltwater (not table, NaCl). Other livestock need to tolerate same conditions. None tolerate unstable, ammonia or nitrite presence; nor much nitrate. Small volumes (under 20-30 gal. depending on species, size) are too unstable.
 Most are killed due to improper environment.

Mollies. Again.       2/14/17
Hi, Neale - long time, no questions! Hope you had a good holiday and that the new year is treating you well.
<All good; thanks for asking.>
This morning we noticed that we have a silver sailfin Molly that's just lying on the bottom or swimming lethargically, using only her pectoral fins. She doesn't use her tail to swim at all. Her tailfin seems kind of shredded lengthwise, but doesn't look bitten. She had gotten big, we thought she was pregnant (assuming one of the 7 young mollies is a male), but she seems slimmer now. We have seen any fry in the tank, though we didn't really look (I'm only just now thinking of it).
We have another Molly, a creamsicle, that is starting to shimmy.
<Typically a stress reaction, though quite what the stress factor might be isn't always obvious. Mollies are easily stressed by chilling, nitrate, and the wrong water chemistry, though like all fish, non-zero ammonia and nitrite are issues too.>

The numbers are good in the tank - ammonia and nitrite are 0, nitrate is 20.
<Sounds good, but no mention of water chemistry here. Will (re-) state the importance of carbonate hardness to Mollies; alkaline water with a basic pH is an essential, especially if salt is not added to the water. Tanks will acidify between water changes, and this causes problems for Mollies in particular. Simply doing a substantial water change or three will often help Mollies return to their normal happy selves. Failing that, adjusting water chemistry slightly, by the addition of sodium bicarbonate -- one teaspoon per 40 litres/10 US gallons is a good start. Easiest approach here
is estimate size of tank, make up the correct solution for that volume, and then add to the tank in small amounts across a few days, giving time for the fish to adapt. Alternatively, just add the right amount of a given bucket of water (so might easily be a quarter teaspoon for a 2.5 gallon bucket) and do your water changes as per normal. I do prefer to keep Mollies in low-end brackish conditions, but understand that isn't an option in all cases. Read up on the pros/cons of this, and act accordingly. Would also check the heater, and maybe turn it up a notch, Mollies preferring quite balmy conditions compared with standard community tank fare; 28C/82F is not out of line for the bigger, sailfin varieties in particular.>
Tell me what I forgot to tell you and I'll provide the info, but this is about it, that I can see. As always, thanks so much for your help!
<Most welcome.>
Tom & Maria
<Cheers, Neale.>

re: Mollies. Again.     2/14/17
The water is relatively hard, and it goes in at around pH 7.8, then the tank adjusts up to 8.0 to 8.2 with the bubble stone and stays there. Maria changes the water weekly at a 25% change. The numbers have all been stable NH3/4, nitrate, nitrite, pH, etc, for months.
She's still hanging in there, but in a head up position. Could this be bacterial?
<Yes, but environment is what you look at first.
If you're content that the tank is good, then sure, treat with an antibiotic. Livebearers are sometimes given to strange "wasting" diseases after a certain length of time -- whether old age, dietary shortcomings (do bear in mind they're herbivores in the wild), social stress, or inbreeding is hard to say. But colonies of livebearers frequently do well for years, but individual fish may have substantially shorter lifespans than you might expect.>
Why would the tail separate into lengthwise strips?
<Typically physical damage, such as fighting. Do bear in mind Mollies are prone to fighting. You could medicate as per Finrot, but keep a close eye on the fish for evidence of squabbling. Cheers, Neale.>

And now, weird Molly behavior. Env.    6/17/16
Neale, I hope this finds you well.
<Likewise my reply, Tom.>
We have another problem - we have a Molly that is spending a lot of time on the bottom. She'll occasionally sort of raise her head and shake it back and forth and then stop and sit there for a while, until she does it again.
<Shimmies. Quite common among Mollies, and indeed livebearers generally, when stressed. Usually, fixing the environment will effect a recovery. No medications as such required, but if there's something else amiss, like odd
white patches on the body or sudden loss of weight, then treating as per a bacterial infection is a good idea. If the only fish in the tank are Mollies (or other livebearers) then adding salt, 2-3 gram/litre, can help a great deal.>
She was doing that this morning then started swimming like a maniac, sometimes stopping and wiggling. The male lyretail did that with her. Now she's back on the bottom. Ok, Maria just opened the top to get some water for testing and the Molly was up to the surface in a flash. Her appetite has been... vigorous this whole time. She just acts funny when she swims (swims into plant leaves, then backs up and swims around them) and spends a lot of time just sitting on the bottom in out of the way places. Poops a lot.
Water numbers:
pH: 7.4 - 7.5
<What sort of hardness level? Mollies appreciate very hard water.>
Ammonia: 0.75
<Still not zero! Mollies are super-sensitive to ammonia and nitrite in freshwater tanks.>

Nitrates/nitrites: 0
Water gets 25% change weekly, but we haven't been adding bacteria to the 38 gallon tank with water changes.
We just don't know if she's even sick, just acting funny. We had one Molly with some white spots that got lethargic and died and took another well-loved fish with her. (We quarantined them, added some conditioner and PimaFix for fungal infections, and the next morning the pH had dropped from 7.4 to 5.8. Both fish died.) So we're a little skittish, I guess.
So there's a lot of info. Any light you can shed on any of it, we'd appreciate it. Thanks a lot!
<Hope this helps! Cheers, Neale.>
Re: And now, weird Molly behavior   6/17/16

Good info, as USUAL - thank you so much! Hardness might be a problem. We have soft water. Would hard water be a problem for the tetras and the platy?
<Platies will usually thrive in the same conditions as Mollies, though Mollies do prefer more heat than Platies; Platies are optimally kept around 22-25C/72-77F whereas Mollies are more 25-28C/77-82F sort of beasts. But so far as water chemistry goes, both like hard, alkaline, basic conditions.
Tetras are predominantly soft water fish, with a few exceptions. Generally not good companions for Mollies because of this. That said, it will depend on your tetras. X-Ray Tetras, Black Widows, 'False' Penguins, and Emperor Tetras will all do just fine up to 20 degrees dH, PH 8, which is fine for Mollies. You can add baking soda, sodium bicarbonate, to raise hardness. Do read:
Something like a half teaspoon baking soda per 20 litres/5 US gallons would be about right. Use a test kit to check before adding any such water to your aquarium.>
These will likely be the last mollies we get. Sheesh.
<As I've said many times, Mollies really aren't community fish and shouldn't be sold/bought as such. They are very beautiful, yes, but quite demanding. Kept on their own though they can look superb! Big tanks with big groups are wonderful. Check out Liberty Mollies some time. I saw a group of them in a single-species set up, designed with lots of flat rocks for them to graze on. Really beautiful fish, and patriotic too if you happen to live in a country with a red, white and blue flag! Cheers, Neale.>
Oh, crap...      8/21/16
We got rid of the mollies. But there's still some ammonia
in the 38 gallon tank - less than 1, more than 0.5. It looks like a ghost tank. We've lost two white skirt tetras, and now nobody is swimming.
<But no sign of Whitespot any more?>
Even the 12 neon are sitting towards the bottom in a clump, swimming a bit, but low in the tank. The remaining white skirts just hang and our platy is just sitting on the bottom.
<Do lower the water level a bit so there is more splashing. Is the water moving briskly? Is the water too warm? The fish behaviour could be related to low oxygen level. Review, and act accordingly.>
The pH is 7.2, no nitrites, a wee trace of nitrates, water is soft, alkalinity around 80. We have added ammo lock and bacteria. I'm afraid were going to lose the tank.
The other tank is fine, even though the ammonia has been higher. Could our filtration be too weak? Gah!
<A typical community tank needs to have a water turnover rate around 6 times the volume of the aquarium per hour. So if you have a 38-gallon aquarium, you'd buy a filter rated at 228 gallons/hour. You can find this value on the filter pump or the packaging. Pretty much ignore anything stating "suitable for tanks of 10-40 gallons" or whatever, because these
are really optimistic values assuming spotlessly clean filter media and very low stocking densities of small fishes such as Neons or Guppies. Much better to use the turnover rate. Provided you have that sort of turnover rate, and assuming the media is appropriate (i.e., biological filter media rather than, say, carbon), mature (over 6 weeks old) and properly
maintained (you don't clean the media under a hot tap) then the filter should be adequate. Check the ammonia level of a sample of dechlorinated tap water. If the ammonia level is identical, then the ammonia test kit is probably picking up neutralised tap water ammonia or chloramine, neither of which are a worry. I find nitrite test kits more useful because they're less likely to be related to tap water, though occasionally tap water does contain nitrite. Cheers, Neale.>
Re: Oh, crap... it's ich      8/21/16

The white skirts have it. We see spots on their fins, looks like the pics we've seen. Everything we see about all this stuff is contradictory - one says do this, next one says do the opposite, third one says do nothing. And thus all started with those mollies.
<Usually Whitespot gets into a tank via the addition of new fish. Once eliminated, the aquarium is normally free from Whitespot until something else is added from the pet store. If this was me, I'd be treating using salt/heat, as described earlier, or else using a proprietary medication, my personal favourite in terms of safety and value being eSHa EXIT.>
So, 38 gallon tank. Four white skirt tetras, twelve neons, one platy, and a Pleco (algae eater). Live plants, which are replaceable. If you can give me one suggestion, one plan of action, maybe we don't need to turn the aquarium into a bookcase.
<See above. Assuming you don't have carbon in the filter, commercial Whitespot medications are very effective. So is the salt/heat method if done right (2 gram/litre of water; temperature up to 28 C). If Whitespot is the issue here, either of these will fix it. Once that's done, your aquarium should be parasite-free. As for the ammonia, do see my previous email re: ammonia in tap water.>
Maria's doing multiple water changes to deal with spiky ammonia levels.
<Don't change more than, say, 10-20% per day. And if the filter is basically functioning right and of adequate size, you should be able to scale these back within a week to the usual 20% change per week.>
Down to 0.5 - 0.75, not zero, but low. This is supposed to be fun and relaxing. �� Gah.
<It is fun and relaxing. Once a tank is set up properly and given periodic water changes, fish are BY FAR the easiest and cheapest pets around. Virtually no work. The problem is if the tank isn't quite right, and more often than not, that's through setting it up wrong, such as buying too many fish too soon, not getting compatible fish, etc. Still, compared to a sick dog or cat, fish are cheap! Have you visited a vet recently?!>
Sorry, and thanks.
<Welcome, Neale.>

One day I saw that my Molly had a white line growing on the top of its head       3/30/16
and I'm worried cause it wasn't there before. I have attached a picture of my Molly and the white line
<Mmm; this white line looks to be some sort of physical injury... perhaps the fish jumped or swam into something that scratched it. Is your water hard and alkaline? Do you add a modicum of aquarium salt? IF your water conditions are propitious and you're feeding your fishes well, this issue will likely heal itself in time. I would not specifically add some sort of medicine/s here, as they're more likely to cause trouble than cure.
Bob Fenner>

re:       3/30/16
There is a small amount of aquarium salt in the water my water is fine, said the lady at the pet store, the only thing that's wrong is my ammonia is high
<Ammonia is deadly toxic. READ here:
and the linked files above. BobF>
re: Keep Reading!       3/30/16

Would that cause my Molly's wound not to heal? Or cause it to grow?
Neale to the rescue!       3/30/16

One day I saw that my Molly had a white line growing on the top of its head and I'm worried cause it wasn't there before. I have attached a picture of my Molly and the white line
<Very odd. The photo isn't sharp enough or close enough to see exactly what's going on. Is it that some of the scales are simply white? This sort of colour change can happen and isn't a health issue as such. Or is there something white, almost like paint, across the back of the fish? This is very commonly seen on Black Mollies and other dark-coloured Mollies when they produce extra mucous. This is usually what happens when they're stressed or irritated by something, either an early bacterial infection or exposure to the wrong environmental conditions. I'm going to direct you to some reading:
Mollies are prone to Finrot and fungal infections when kept in plain freshwater. In brackish water they're a lot tougher, and by brackish, I'm talking something like 5-6 gram/litre (3-4 teaspoons of marine aquarium salt mix per US gallon). Although brackish conditions aren't essential, they help. If that isn't an option, then do make sure the water is very hard (15+ degrees dH) and relatively warm (25-28 C) and above all else keep nitrate as low as practical (20 mg/l or less). Naturally, ammonia and nitrite levels should be zero. Cheers, Neale.>
re:       3/30/16

There is a small amount of aquarium salt in the water my water is fine, said the lady at the pet store, the only thing that's wrong is my ammonia is high
<I'd love to know what the "lady in the pet store" means by the word "fine" if your water has high ammonia! Let's be clear, subjective interpretations of water chemistry and quality are about as useful to us as you telling your doctor that "you've got an owie on your booboo". So please, write back when you have some actual numbers. To recap, as always with fish, and nitrite must be zero. If they're not, then stop feeding and review the aquarium. Non-zero ammonia and nitrite imply three things: overstocking, overfeeding, and/or insufficient filtration. This last one is key, and you can have insufficient filtration because the filter is too small, because you are not maintaining it properly, or because the filter hasn't had the 6-8 weeks it needs to mature. Review, and act accordingly. As for the other
water parameters, in freshwater conditions you need low nitrate (<20 mg/l);
high pH (7.5-8.5); and high hardness (15+ dH). In brackish conditions Mollies are less demanding, but that will of course limit your choices of tankmates. Nonetheless, they're commercially reared and bred in brackish water for precisely this reason, and if you're specialising in Mollies, adding 5-6 gram/litre marine aquarium salt mix (not tonic/aquarium salt) will massively simplify your fishkeeping experience. Cheers, Neale.>
re:       3/30/16

Would that cause my Molly's wound not to heal? Or cause it to grow?
<Dissolved ammonia is to fish what Cholera bacteria in drinking water is to humans: deadly, and able to cause all kinds of problems. So when people say "a trace of ammonia" is in their fish tank and think that's fine, to me
that's liking offering someone a bottle of mineral water with a "trace of Cholera". Not nice, huh? Cheers, Neale.>

re: Just to update you on my molly.        4/7/16
I did take all of my fish out of the tank
temporarily into another fish tank that I have. I changed the water and tested it one more time with master test kit, which is a drop test. My ammonia was 4.0ppm... yea that isn't a little high no wonder why my fish were dying and my Molly wasn't healing.
<I agree!!!>

My Molly apparently scratched it's head trying to get into my tiki head, I guess she learned that she's to big for a few things haha. So now my fish is all healed and my aquarium is back to normal, meaning having an ammonia level of 0, I am also feeding my, now 3 fish, once every other day and I'm also keeping a close eye on all their levels. And I'm thankful to day that I'm not going to that petstore ever again, and I'm also doing a lot more research into everything that I do and every fish that I get. :)
<Not saying avoid your local pet store, but do keep an open mind, and as the Russians say, "trust, but verify". Double check what they tell you against a trusted book or website. Obviously this one's good, but there are others I wholeheartedly recommended. TFH, FishChannel, SeriouslyFish, PlanetCatfish, Loaches.com, ThePufferForum.com ... all good sources of info and accessible to all.>
you will most definitely hear from me again this is the best help that I've ever found.
<Thanks for the kind words. Neale.>

pop eye molly?     12/4/14
Hi all, sorry to bother you guys again. My roommate just got her tank and moved her fish from mine to hers so I'm back down to six fish in my tank. (with her fish there were eight fish and her two were several inches long) I came back from vacation and found two of my fish dead. I wasn't totally surprised since at the time the tank was very overcrowded and it was the smaller fish that had died. Well the issue was that the water was all yellowish brown from the fish being dead for a while in the tank (that what the pet store said) so I bought some clear water solution to help.
<... poor. CHANGE a good deal (like a quarter) of the water out every other day until it clears>

I treated the tank twice and afterwards the two fish were removed and put into another tank. One of my fish i believe is depressed as he and the male sailfin were pretty good buddies. I was feeding my fish this morning and I noticed that my female sailfin molly has her left eye bulging out slightly, just enough to notice and make her look weird. What can I do to help her?
<The above; water quality improvement, not "drops"... which will do nothing to improve it>

Also what can I do about my male's "depression" as he sits on the bottom since we moved the other fish.
<The exact same. READ on WWM re Molly Systems. Bob Fenner>
Re: pop eye molly?      12/4/14

Hi again. I just got back from class and my sailfin molly female (the one with both eyes slightly bulging) was sitting on the bottom. After a few minutes she got up and swam around and went right back to laying on the bottom. I just did a 50% water change and added some aquarium salt.
Is there anything else I can do to help with the eye bulging or will it go away on its own. I feel really bad for her. I plan on getting the water tested tomorrow to see what all the levels are. Another question is what is the best way to transport fish?
<Covered on WWM...>
I'm moving back home from college next week and I'm not sure how to move my fish. It is a 2 hour drive.
<Perhaps a bit of Epsom... see WWM re. BobF>

URGENT MOLLY HELP       12/5/14
I wrote to you guys the other day about my Sailfin female having PopEye on Wednesday. On Thursday I noticed that he eyes were back to normal (a very tiny amount of bulging but almost undetectable. Only noticed as she was right next to my Dalmatian molly male.) Today however, I noticed her eye was popping out again and her other eye had started to.
<When both eyes "pop" it's almost always some sort of environmental shortcoming. As always with Mollies, review the key basics: test carbonate hardness and pH (water needs to be hard and alkaline); test for nitrite or ammonia (water quality needs to be good); test for nitrate (this should be as low as practical). How much salt are you adding? With Mollies, brackish water is the ideal in the sense they tend to be much hardier and more resistant than in freshwater. To stress a point made many times here:
Mollies are not easy community fish, and can't be thrown into a planted tank or a regular community tank alongside soft water fish. They need very specific conditions. There's no medicine for Pop-eye as such, but the addition of Epsom Salt to the water (1 to 3 teaspoons per 5 gallons/20 litres) plus raising the temperature a couple of degrees can effect a cure provided the stress factors in the environment are fixed. Note that Platies will tolerate brackish water well (not less than 5-6 gram marine salt mix/litre in this situation) but soft water fish and most plants will not.
As I say though, you should only choose Mollies for tanks where you have the option of adding salt if needs be, and it sounds like you do.>
It got worse over the day so I put her in a small hospital/transport tank for several hours. Her eyes went back down quite a bit so I put her back.
Now all my fish are attacking her. My male molly and female balloon molly are chasing her everywhere along with my female bumblebee platy.
<Mollies are not sociable fish when kept in very small groups; often much better in large tanks and large numbers. Not a suitable species for tanks smaller than, realistically, 30 gallons, unless you keep just a singleton.
Sailfin Mollies in particular can get huge (15 cm/6 inches) under ideal conditions in the wild and not less than 10 cm/4 inches in aquaria, so anything less than 30 gallons is clearly unsuitable.>
I can't keep her in the "hospital" tank as it is really just a small animal carrier. She is now hiding in the barrel that I have which she has never gone in before. I'm worried about her. What can I do to help. I really like her as I was hoping to use her to start a small breeding operation (2 females and one male) of Sailfins. This is the picture of the hospital tank and her hiding from the others.
<Meantime do read:
And follow the links to Molly Disease and Molly System FAQs; the problems you are experiencing are very common and easily prevented. Cheers, Neale.>
URGENT MOLLY HELP.... the reading?        12/5/14

I wrote to you guys the other day about my Sailfin female having PopEye on Wednesday. On Thursday I noticed that he eyes were back to normal (a very tiny amount of bulging but almost undetectable.
<Excellent. As stated in my previous reply, environment is both the cause and cure of Pop-eye in such situations.>
Only noticed as she was right next to my Dalmatian molly male.) Today however, I noticed her eye was popping out again and her other eye had started to. It got worse over the day so I put her in a small hospital/transport tank for several hours. Her eyes went back down quite a bit so I put her back. Now all my fish are attacking her. My male molly and female balloon molly are chasing her everywhere along with my female bumblebee platy. I can't keep her in the "hospital" tank as it is really just a small animal carrier. She is now hiding in the barrel that I have which she has never gone in before. I'm worried about her. What can I do to help. I really like her as I was hoping to use her to start a small breeding operation (2 females and one male) of Sailfins. This is the picture of the hospital tank and her hiding from the others.
<Do read the other email. Write back if you need help. Cheers, Neale.>

Re: URGENT MOLLY HELP...  not what WWM is     12/7/14
Thanks . I'm going to get the water tested today. I will be moving home on
Friday (i live in a dorm) so I think a fresh start on the water will be
good for her. I do plan on getting a larger aquarium for these guys as I
want to put my Betta in the 10 gallon so he will be happier. I do have
aquarium salt in the tank currently and it does seem to help.
<For sure. "Aquarium salt" isn't the same thing as marine aquarium salt, and as/when you've finished the existing package of salt would be a good time to switch. Won't much affect cost, but marine aquarium salt raises not just salinity but hardness, pH and buffering capacity too -- all big plusses for the Molly aquarium.>
Thanks so much for all your guys help and for putting up with crazy me. As
this is my first time with an aquarium I tend to freak out when things go
<Nothing wrong with being concerned.>
Here is a picture of my tank.
<Looks nice!>
(three fish aren't in here as they are camera shy)I also got my water
tested and figured out the problem. Ammonia - 0.25 mg/l
<That's your problem right there. Ammonia above 0 is toxic, and Mollies are
ammonia-sensitive in freshwater tanks.>
Nitrite - 10.0 mg/L
<Lethal! I'm guessing you mean 1 mg/l since 10 mg/l would kill most fish
within hours. Together with non-zero ammonia, non-zero nitrite suggests
overstocking, overfeeding and/or under-filtration. Review, and act
accordingly. Short term: stop feeding, do daily water changes, and check
the filter is working/appropriate to this aquarium in terms of size,
Nitrate - 60-80 mg/L
pH - 8.4
Alkalinity - 300 mg/L
Chlorine/Chloramine 0 mg/L
<All fine. Cheers, Neale.>
Re: URGENT MOLLY HELP chatting, chatting... 
The pet store said it was at ten she was surprised and told me to do a
water change.
<A water change is an understatement! At 10 mg/l nitrite, you'd have to remove the fish to a bucket, change all the water, then reintroduce the fish. Alternatively, change 50% now, 50% after an hour, and 50% after another hour. This really is lethal. Meantime, do not feed the fish until ammonia and nitrite are 0. Seriously. No food. Even two weeks without food
won't harm them, but further exposure to non-zero ammonia and nitrite will.>
She also gave me a product to help with the levels
<Do understand no chemical will magically make water safe from ammonia and nitrite. There is really only one "bottle" you must use. This is water conditioner. In your situation, the only other product you might consider is a bottle of filter bacteria (such as Tetra SafeStart). These products are very hit-and-miss in terms of working. Sometimes they help, something they don't. But they're cheap and worth a shot in a crisis. Otherwise, the only way to eliminate ammonia and nitrite from your fish tank is a working filter. Find out why yours isn't working. Is the tank newly set up? Is the filter big enough for your tank/number of fish? Do you have the right media in the filter? (As a hint, carbon is useless while sponges and ceramic noodles are essential.) Is the flow rate normal or slow because the filter is clogged? Is there enough oxygen for the bacteria? Is the tank overstocked? Are the fish overfed? Is there a corpse somewhere rotting away? Various possibilities. Cheers, Neale.>

Re: URGENT MOLLY HELP...    12/8/14
Hi again. I figured out some of my mollies weird behavior. I put her in the
hospital tank as she was acting weird and this morning I found babies. She
was acting normal. I also did several large water changes yesterday and
changed my filter.
<Sounds like you're making progress. Good luck! Neale.>

Re: URGENT MOLLY HELP      12/8/14
I tested the water and the nitrite and nitrate levels are down now.
<Cool. Keep nitrite at zero, and nitrate as low as practical (below 20 mg/l ideally). Don't feed the fish if nitrite or ammonia aren't zero; do water changes instead.>
Thanks for your help.
<Most welcome. Neale.>
Re: URGENT MOLLY HELP      12/8/14

Hi Neale. A new problem emerged which has happened before. My balloon molly has done this before but it seems worse. She used to occasionally swim with her head facing down and she has been doing it all day and can't seem to right herself.
<Assuming she's otherwise healthy, constipation could be the problem here.
A common problem where deformed herbivorous fish are concerned. Read here:
Treatment involves Epsom salt and plant-based foods.>
She also hasn't eaten even when i put her in the hospital tank. I'm thinking its swim bladder disease but not sure how to treat it. (everything I'm reading says to feed her peas or have a vet x-ray her ((not going to happen)))
<There's no such thing as "Swim bladder disease" any more than a broken leg is a disease. It's a description of a set of symptoms including the inability to orient themselves properly. Constipation is the commonest cause. But Dropsy (associated with raised, "pine cone"-looking scales) and some bacterial infections (alongside disinterest in food, lethargy) can cause similar symptoms. Cheers, Neale.>

Flashing molly. Env., using WWM      9/13/13
I have  a 2 month old  29 gallon tank cycled for 3 weeks  with CaribSea  media containing bacteria. (fish food  added  to  feed  bacteria). Added 4 neons,
<Stop: Mollies and Neons (tetras) are not compatible... water quality nor temperament wise.
See WWM re both, all species>
 after 2 weeks 3 lyre tail Dalmatian mollies, 4 more neons and 2 Corydoras.
Only learned now  the  need  for  brackish water for mollies which I can't address because  of  the  other  fish in the  tank.
<Ah yes>
My question is that I  see  the mollies flashing occasionally,
<Likely the water quality issue you've just mentioned.
Again, just search, read on WWM re their systems... NEED hard, alkaline, cooler, often salty water>
usually against plants especially the pregnant one. If  I  watch  for 30 minutes it  will  flash 1-2 times. I see  nothing  on  their bodies  that  looks like  Ich and  they  seem  active  and  happy, feeding, playing  grazing on plants. I started  treatment with Jungle Ich
<Stop again: The real issue here won't be solved by pouring in "medicines"... The environment has to be fixed>
 clear following  directions for 2  days  now. Still nothing  on  their  skin that I can see (they  are  mostly white) or  on the  other  fish.
Raised  temp to 80.  Still look active and  healthy to me. Is  this  flashing possibly  just normal behavior? I saw  the  Corydoras do it  2  times, never the neons.
<... Read on! Use the search tool, on every page on WWM. Bob Fenner>
Re: Flashing molly.     9/13/13

I am sorry , I should have mentioned that i have checked the  water quality couple of times these past  week. No nitrates or nitrite, chlorine, pH 7.2, total alkalinity 80 (moderate), hardness 75ppm.
<Good; and no ammonia I take it. BobF>
Re: Flashing molly.

The neons and mollies just ignore each other to my eye.
<... they'll soon be dead if not accommodated. READ where you've been referred. B>
Re: Flashing molly.
So this behavior is not "normal". It indicates something?
<Read, don't write. B>
Re: Flashing molly.

I have read and read for 1 week now. It is because of reading I started the medication. What should I read on WWM. Thank you for your help.
and the linked files above
Re: Flashing molly.     9/13/13

my test doesn't have ammonia

Creamsicle Lyretail Molly Trouble and a salt question. Livestock of differing water quality needs tog.     6/13/12
Hello!  Thank you for such an informative site.  I have spent hours and hours reading the wealth of knowledge it provides...yet I still feel unsure about my situation.  I apologize in advance for possible info-overload, but I'd rather err on the side of too much than not enough.  My FIL gifted my 2 year-old daughter a 20 gallon aquarium for her birthday (at my suggestion; I was excited about it also, as well as willing to put forth the effort it requires).  At the time, my idea of keeping fish included water, a bowl, and some fish...little did I know!  Since then, 3 months ago, we have acquired: 3 Neon Tetras (unsure of sex),
<Mmm, these really need different water quality than the livebearers you're keeping... soft/er, more tropical...>

1 male Albino Bushy Nose Pleco, 1 male Lemon Cobra Guppy, 3 male Harlequin Sailfin Mollies, 1 female Creamsicle Lyretail Molly, 1 female Dalmatian Lyretail Molly, 1 male Mickey Mouse Platy, 1 male Sunburst Wagtail Platy, 1 female Red Platy (just died), 2 African Dwarf Frogs, and a single Ghost Shrimp who has survived this
whole time, amazingly enough!  I also have two varieties of live plants: Hygrophila and Cyperus;
<Cyperus? A sedge? Is this emersed?>
both have done really well.  Just this week, I began half-dosing the tank with Aqueon Plant Food (10mL/20 g).  In the beginning we lost a black Platy, and I didn't think twice about it at the time; I thought that fish just died...ce la vie.  I don't remember it having any spots/fungus/weird behavior indicating any of the issues listed on the Disease Troubleshooting page; however, I also did not know that it is best to quarantine new fish. 
We introduced 3 batches of fish within one week of getting the tank set up. 
<Uncycled risks...>

Fast forward to present.  This past weekend we were out of town for two days to come back and discover a tiny red female platy...obviously, the Red Platy had had babies, and we didn't even know she was pregnant.  Having the three females in there was a mistake; we wanted to only have males (is this even a good idea?).
<Can be>
 The reason being, I did not want to have to deal with off-loading baby fish...repeatedly.  Plus, I'm kind of half and half on how I feel about just letting the females have babies and it being a free for all for snack time.  *bag over head*  ...not sure how the experts feel on this?
<A mix as well>
 Yesterday, the female Red Platy died.  She had been sitting on the bottom of the tank, and I read and read and researched and couldn't come to a conclusion as to why she was doing this.  I ran out immediately and got a water test kit (yep, learned that I needed one of those 3 months too late). 
Today I tested the water before and after the cleaning/gravel suction; I replace 25% of the water once a week.
 I add 10mL of Aqueon Water Conditioner each time I do this.  These were my
readings after I changed the water: GH 30, KH 120-180, pH 7.5-8.0, NO2 0, NO3 20. 
<Keep Nitrate no higher>
The temp is always about 78 degrees F; today was the same.  I don't keep a fish heater in the tank, as we live in Arizona and I keep the house pretty warm...free heat!  These readings weren't much different from the before reading...the only difference being the NO3, which was 40 before the cleaning. 
<Too high>
According to the test directions, my GH is too high.
<Mmm, I wouldn't likely "fool with it/this">
  I didn't see the recommended solution
<Blending in some water (RO likely) w/ less mineral content>
 to that at my local pet store, however (API Electro-Right).  Also, is the pH okay, or does it need to come down a bit?  It seems fine for some of the fish, and too high for the others.
<Is high for the Neons, but not for all else>
I have since learned from all my reading that I have overstocked, and that I have mixed Mollies with other types of fish, when they should be by themselves.  I also have learned that by not having enough females to males, I was creating problems with chasing them to death; I'm still not sure why the female Red Platy died.  All of the fish chase each other in there; they always have (the guppy, especially, likes to chase the big Lyretails).  I never see them nipping, though.  I do not plan on restocking as fish die, and I hope to create a happy, safe environment for the ones I have...as best I can.  I have also learned that the frogs prefer to be alone, but these actually don't bother each other (seemingly).
 <Ah yes>
The problem I'm having with the female Creamsicle Lyretail Molly is that she has started floating upright, midtank, in the water.  She looks, occasionally, like she is shivering.
<The metabolite concentration... as "windowed" by your NO3 testing/results... poisoned by their own wastes. Very common>

 I have noticed that on her pectoral and caudal fins, which are fairly transparent, she has these whitish looking spots.  They are fairly bigger than grains of salt, leading me to believe it's not Ick,
<Maybe... though could "just be body mucus clumps"... reaction to water quality issue/s>
 and they aren't in clusters...just a handful all together.  She seems to swim fine when she isn't doing the vertical-hover-shiver thing, and she eats normally.  I noticed this morning that she has some bumps on her head...also fairly bigger than grains of salt.  There's nothing on her body that looks different or "wrong"...no white specs or anything.  I went to the store today with the knowledge from this site and hoped to have the "fish specialist" at my local pet store help me, but that turned out to be a fail.  I did end up spending a good hour perusing the medicines, and ended up coming home with Tetra Lifeguard All-In-One Treatment, but I'm unsure if it what I should put in my tank...?  
<I wouldn't>
Any ideas on what could be bothering her?
<The environment
... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked files above if still unclear>
  I just worry (now that I know better) about something infiltrating the whole tank and hurting more fish. I know (now) that mollies do much better in a brackish environment.
<Ah yes>
  My other question about that is, can I introduce marine salt, considering the other cohabitants and plants? 
<... Mmm, best for you to spend the time "looking up" such information... the Neons "don't like" salts... neither Hymenochirus... the livebearers are fine w/ a modicum...>
If so, do I introduce it slowly, or just go all-in and follow the directions on the box of API Aquarium Salt...which says 1 rounded tablespoon per 5 gallons of water (so 4 rounded tablespoons)?
<... you'll need to investigate, likely move the non-salt livestock elsewhere ahead of the addition>
Because I do have an overstocked tank, would more hiding places be encouraged?
<Mmm, yes>
 Currently, I have a piece of driftwood (fake) that takes up the length and height of the tank (but is narrow) to provide some good shelter, as well as the two types of plants I have now (the Cyperus, of which, has set out about a dozen runners that have sprouted up quite nicely, so I bunched them all in the same corner) and a small pirate ship (at my daughter's request...*smile*).  My idea was to add some plants to grow on the surface of the tank; would this be good?
<Yes; a/my fave Ceratopteris...>
 If so, what kind would you recommend based on my current tank environment?
I do thank you for your time. 
<You have two great requisite traits for being successful (not just w/ pet fish); a curious mind and desire to improve situations... Read a bit and do write back if you are unsure of a plan... to separate (have two systems) and modify water quality to suit the life in your charge. Bob Fenner>

Molly tail down...      4/23/12
WWM, I need help. I have some sick female Silver Lyre-tail Mollies (found a female one 'crashed' at bottom of tank this morning). I suspect the other 2 will not be far behind. Molly #1 has been hiding, shaking and shimmying since she had babies about a month ago. Since she never comes out of hiding I have only recently noticed her tail is drooping down (like her rear-end is paralyzed), there is a curve or kink in her spine so that tail is curled to side and fins are clamped. Also her eyes look 'fluorescent' blue with same coloring on top of body. Molly # 2 has had buoyancy issues for about 2-3 days with keeping her tail down and head up, today this seems better but she is swollen, clamped fins.
Molly #3 died with a swollen stomach, all 3 have(had) high-arched back (hump?) and low appetite. Gave all 3 a salt dip in similar water parameters of 1 gallon + 1 tbsp of Epsom salt for 5 minutes and placed back in tank yesterday. Today gave an additional dip to the 2 remaining only for 10 minutes. Have seen them scratch a couple of times here or there, but not constantly or even every day. Parasites? TB? Fungus? Lack of electrolytes?
<Likely the last... plus exposure to metabolites... Most common causes of Molly demise>

 Help :(  Also, in my 'baby' tank (20 g tank dedicated to the Fry of all the parent fish) the white mollies swim vertically (head up). They CAN swim normally, but at times they don't; they move forward (like belly forward) just straight up and down as if they were constantly swimming against a glass wall. What is this???
<The same>
Details of our tank: 30 g with 11 total of guppies (2 females, 1 male), platies (2 males-1 that can't breed, long story, 3 females) and 3 mollies (2 females, 1 male). Also have about a dozen (can't keep track) babies that have stayed hidden and recently came out because they seem to be too big to be eaten (parents don't chase them or anything) they could be anywhere from a week-2 weeks old so I don't see the need to move them now. We do 30% weekly water changes and keep a 78-79 degree temp and ph of about 7.6. Don't know the rest of the parameters but get it tested at the LFS and we are told it is 'fine.'
<Of no use... need to know specifics... esp. nitrogenous/Nitrate accumulation>

Keep aquarium salt (or canning salt when we are out of the other)
<Sea salt (marine) is what you want>

 at rate of 1 tbsp per 10  gallons. Also, recently learned about adding baking soda (yesterday) and added 3 tbsp of baking soda diluted in tank water over about 30 minutes.  I know that Mollies are harder than guppies and platies to keep but is this a species problem or something else going on?
<Most all mollies kept in captivity nowayears have troubles... really need to be kept in large brackish to marine settings>

Do I need to set up a 3rd tank and keep my mollies in their own tank from now on?
Sorry, I am not able to send pics (they are not clear) or video (Silverlight is dumb).
<Please read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm
and the linked Molly Disease FAQs files above... all will be revealed. Bob Fenner>
Re: Molly tail down    4/28/14

Thank you so much for your quick and reliable responses to all of my questions! I am really not sure if my 2 female Mollies are on the mend or not. We are taking everything 1 day at a time. However, the 20 gallon tank, that I mentioned in my previous email that houses several batches of fry, is giving me cause for concern. The latest batch of fry that we added are 10 day old guppies. Several of them seem to have 'bent' tails and 1 of them has an extremely bent tail and is swimming around in circles,
<Bad... might be congenitally (genetically) troubled... could be due to nutritional deficiency, even some aspects of water quality>

being carried wherever the water takes it. It will then rest on the bottom a minute and then start again. Also, this fry has a very black tail, back, and head with a silver belly which is very different from the other fry and parents. Is this whirling disease?
 I've read about it on your sight <site> but wasn't sure if fry this young could get this disease.
Details of the tank: 20 gallons with a mixture of probably 50 fry: guppies, Platies, mollies. Ages range from 10 days old to about 3 weeks. We do about a 20% weekly water change and keep a 78-79 degree temp and ph of about 7.6.
Don't know the rest of the parameters but get it tested at the LFS and we are told it is 'fine.'
<Past time to have/use your own test kits>
We are still working on getting the proper testing strips.
<See WWM re... inferior technology>
 Keep aquarium salt  (or canning salt when we are out of the other, and we are also working on getting Marine salt as well as looking into Kent Iodine) at rate of 1 tbsp per 5 gallons (not 10). Also, added baking soda at rate of 1 tbsp per 10 gallons.
Thanks for all advise! -Amelia
<Not advice; just what I/we might do given similar and supposed circumstances. Bob Fenner> 

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.>

Dalmatian Molly Sitting at Bottom of Tank (ammonia, no salt, the usual...) 8/8/09
Hi -
My apologies up front for what are likely some basic questions, but I just got a new tank a little over 4 weeks ago and the thing didn't come with an idiot's guide to setting up and caring for an aquarium and the fish in them.
<We consistently suggest you buy (or borrow) a book before anything else.
Sure, you miss out on immediate gratification, but sometimes learning about a subject before you dive into can make all the difference.>
Most of my problem stems from the fact that every person I ask at PetSmart has a different answer - and none of them seem to be right!
<Indeed. Here are some thoughts on selecting livestock for the first aquarium:
I have a 29-gallon tank with 2 Neons, 2 guppies, 1 Mickey mouse platy, and a Dalmatian molly. I was waiting to populate the tank more until the tank had stabilized.
<Mollies are, essentially, incompatible with most other community fish.
Platies and Guppies happen to be livebearers and will tolerate slight salinity well, but the Neons won't. Do read here:
If you want Mollies, you should add a little marine salt mix -- not aquarium or tonic salt -- to the water. This steadies a basic pH, adds some carbonate hardness, and increases the salinity, and all three of these things are helpful with Mollies.>
I woke up this morning to find the molly sitting at the bottom of the tank - an occasional move of the fins or shifting on the rocks, but otherwise, just sitting there. When I fed the fish this morning, the molly (usually
the one eating far more than its share) just stayed along the bottom and ignored the food. I don't see any of the fungal disease signs mentioned in the other FAQs, though I suspect water quality is the issue.
<So do I.>
When I got the tank, I was told to change 30% of the water once a month.
So just shy of one month in, I brought in a vial of water to PetSmart to have it tested and found out the ammonia levels were not toxic, but pretty darn close.
<Hmm... ammonia is toxic at any level other than zero, end of story, so if the PetSmart clerk said the level was above zero but not dangerous, he/she was either lying or ignorant. Mollies are especially sensitive to ammonia when kept in freshwater tanks.>
I was told to change 30-40% of the water and that should take care of the problem. I did so by vacuuming the gravel and took the water to be tested again several days later. The pH levels were too high and the ammonia hadn't dropped at all. They gave me a pH decrease and ammonia remover and told me to change the water again and add those.
<This clerk is having a laugh at your expense. Ammonia is a basic substance, i.e., it raises the pH. So long as you have non-zero ammonia levels, you'll have a pH higher than it would be without ammonia.
Furthermore, Platies, Mollies, and Guppies all want a basic pH, around 7.5 to 8.2.>
I did that and took yet another vial in a few days later. The pH had balanced, but the ammonia was still too high - and this person told me the pH decrease and ammonia remover were worthless. This person told me to change the water again and add stress coat. I did - and ended up changing about 50% of the water. Took another vial in this morning after seeing the molly at the bottom of the tank and was told that the ammonia levels were still too high (I think they were around 3?).
<3 mg/l is very toxic. If 0.3 mg/l, that's a typical background level to see in an immature aquarium. In the short term, this is likely to trigger Finrot and Fungal infections, even if it won't immediately kill your fish.>
They told me to not change the water for a week because the molly is likely stressed out from all the water changes (3 in the last 10 days).
They told me to add more stress coat today and change 25% of the water in one week's time. I added the stress coat. They also told me I was likely overfeeding the fish - two times a day. They said to feed them only one time every other day - sounds like very little to me.
<Whilst maturing a tank, feeding every other day is about right.>
Not a one of them suggested that the molly would do well with a little salt in the water - so there's none in there.
So here are my questions. Do you suspect that it is a water quality issue?

Should I wait a week to change the water or is the "fish is stressed out" theory incorrect?
<No, don't wait. The theory is rubbish. Do regular 10-20% water changes, daily if necessary, to keep ammonia and nitrite as low as possible through the cycling phase.>
Can you change the water too often?
<Provided pH and hardness and temperature are the same in the new water as the aquarium, no. In practise, for a tank being matured, changing around 20% every day or two is an extremely good idea. After 3-4 weeks, the tank should be cycled, or pretty darn close, and you can fall back to the usual 25% per week.>
Should I add some salt or will that impact the other fish negatively?
<Remove the Neons to another aquarium, and then add 3-5 grammes of marine salt mix (the stuff used in marine tanks) per litre of water.>
They told me to change the filter at the time of my first water change - which I did. Did I lose some or all of the good bacteria in the tank in the process?
<The filter bacteria are in the biological filter media, typically sponges or ceramic media. These should be rinsed in a bucket of water taken from the aquarium during a water change. Clean these every 4-6 weeks, more often if the filter gets clogged easily. Chemical media, things like carbon, if used, should be replaced once a month; there's no point cleaning them.>
How often would you feed them?
<Initially every couple of days is fine. Once the tank is cycled and ammonia and nitrite are zero, feeding a small pinch daily should be ample.>
Since I can't get a straight answer out of the PetSmart people, should I invest in my own water testing strips and the internet for answers?
<I know it's heresy in this lazy age of instant information, but books are what you want. Books are written by experts (people like me!) and edited professionally to make sure the facts presented are reliable. Your public library will have a selection of books on fishkeeping, even if you don't want to part with the $10 required to buy one. Failing that, WWM has lots of detailed articles on every imaginable aspect of the hobby.>
Where can I find that idiot's guide to keeping your fish alive?!
Sorry for all the questions. I've been on the web a good chunk of the evening trying to figure out what's wrong with the molly and this site seemed to be the most informative and helpful. Seemed the right place to
unload all my "help, I'm a rookie" questions!
Thank you for your time and help. I'm really hoping to get that molly back up and swimming about...
<Once provided with clean, slightly salty water it should pep up.>
<Cheers, Neale.>
Re Dalmatian Molly Sitting at Bottom of Tank (ammonia, no salt, the usual...) 8/8/09
<Wasn't clear with this answer...>
Should I wait a week to change the water or is the "fish is stressed out" theory incorrect?
<No, don't wait. The theory is rubbish. Do regular 10-20% water changes, daily if necessary, to keep ammonia and nitrite as low as possible through the cycling phase.>
Re: Dalmatian Molly Sitting at Bottom of Tank (ammonia, no salt, the usual...) [RMF, please edit the Daily] <?>  8/10/09
<<Neale: What does this mean? BobF>>
Hi Neale -
Thank you very much for all your helpful advice.
<Happy to help.>
I went in and changed a little over a quarter of the water with a (hopefully) very thorough gravel clean and the water is looking a whole lot clearer. I'll keep doing daily or every other day 10% water changes until things stabilize and add a little marine salt once I'm able to get the Neons out of there.
<Very good plan.>
We'll see how things go, but regardless, the molly was swimming around this morning and seemed much more active. Thanks again!
<Yes, Mollies often respond quickly to beneficial changes in their environment. This is the flip side to the point made last time about how badly they react when kept inappropriately.>
<Cheers, Neale.>

Mystery Mollie Illness? Reading   8/24/08 Hi there! Thank you so much for taking time out of your lives to create this site for us. In my ten gallon tank <Mmm, small... volumes are hard to keep stable> I currently have three bronze cories, one Otocinclus, two silver mollies, two Dalmatian mollies, and a Crowntail Betta ( perhaps you'll tell me it's overcrowded but I have not had any problems with nipping or bullying.) I'm having some problems with one of my female silver mollies. Her dorsal is clamped and she has a slight pink hue on the top of her head between her eyes. She also has a dusting of tiny black spots across her body and the edge of her dorsal is black when looking at it from the top. Her gills also seem a bit more pink than usual. I thought it was fin rot, but after a round of Melafix <... not a fan. Little practical use, and can malaffect nitrification> and Tetracycline I didn't see any improvements. I treated the whole tank but am now considering separating her and beginning anti-parasitic treatments. I was thinking of velvet as an initial possibility, but the spots seem too dark for that. All the other fish seem fine. All advice would be most appreciated!! Oh, and water conditions are: pH - 7.0 Temp - 78 F Nitrates, Nitrites, and Ammonia are all at 0 <Good> I also add a few teaspoons of aquarium salt and Aquarisol <Mmm, I wouldn't use this... the copper is too toxic> every time I change the water (about 50% every two weeks) along with the typical water conditioner. It is a lightly planted tank with gravel substrate. Thank you so much! <I suspect the usual trouble with mixing Mollies here... Inappropriate environment. Please read Neale's piece here: http://wetwebmedia.com/FWSubWebIndex/mollies.htm  and the linked Disease FAQs above. Bob Fenner>

Molly issues. Hlth., env.   3/3/08 Hello, and I hope you can help. I've searched through the archives and I have a problem that seems to be a combination of things. I had two mollies in my ~7 gallon tank. <Too small... Mollies are hypersensitive to fluctuating/poor water quality, and simply don't do well in small tanks. 20-gallons is the minimum. To be honest, a 7-gallon tank isn't much good for anything; even an expert fishkeeper will have trouble keeping stuff alive in there.> The first molly has unfortunately passed, probably due to my ignorance (the pet store did not inform me of the semi-intense care that mollies require upon my purchase). <Not sure "intense" is the word; but yes, Mollies have very specific needs. Ignore them, and they die. End of story. Do see here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  Unless you are an expert fishkeeper (and forgive me if you are) then I would recommend, nay, insist, you keep Mollies in brackish water. They are altogether hardier under such conditions.> I am attempting to save the remaining molly, but she is showing some of the same symptoms as the one that perished. They are both Dalmatian mollies. I did not have a heater in my tank, so I think the first molly may have gone into shock which may have depressed his immune system. <Why no heater? Mollies are tropical fish, and in fact like water a bit on the warm side; 26-28 C seems to be the optimum, and certainly never less than 25 C.> The second molly is now hanging out at the bottom of the tank. She seems hungry, but when she attempts to eat the flakes that I give her it looks like she is spitting them back out, then hungrily goes to the next flake only to spit it out again. <Fish will spit out food if they are not hungry or don't like it. Try something else. Frozen bloodworms (not freeze dried) and algae-based flake foods are the staples for these and indeed most other Poecilia. Generic flake foods aren't really what they want/need.> I noticed my first molly doing the same thing, but she never did until now. When she has evacuations (she must be eating something), they are generally long and occasionally have a long trail of transparent mucous-like substance trailing them. <Evacuations? Is that a euphemism for defecation? If what we're talking about is the faeces are long, stringy and pale, then that doesn't necessarily mean disaster but it can indicate lack of overall health, constipation, etc. Lots of people forget Mollies are herbivores and feed them standard tropical flake food. This is not good for them. They need algae, algae and more algae!> I tried giving her spinach yesterday because I read on your site that the issue may be constipation, but she didn't touch it. I don't notice any growth on her gills, but she is much more lethargic than she used to be. I've only had her for about two weeks. <Sounds doomed to me... Unless you're prepared to raise your game here the fish isn't going to live long.> I put a pH-balancing tablet and an ammonia-eliminating tablet into the water. <What on Earth are these items? OK, let's make this crystal clear: there is no such thing as an ammonia-removing tablet. If they sold you this in the store, they obviously see you as the perfect customer, i.e., you'll buy anything. What makes ammonia go away is the biological filter, which you (I hope) have in place by cycling the aquarium for 4-6 weeks before adding any fish. Or else you took live media from another tank. But please tell me what you didn't do is stick two Mollies into a brand new aquarium. If you did, you may as well have stuck your fish on the barbecue for all the chance they'll have of surviving. Now, the "pH tablet" is something you should stop playing with. At this stage in your fishkeeping career you should not even be thinking about changing the pH or hardness of the water. You first test the pH and hardness of your tap water, and then you buy fish that will thrive in it. If you have soft water, but want to keep livebearers, then buy some MARINE salt mix, and add a certain amount (I'd recommend 6-9 grammes per litre) into each bucket of water added to the tank. Mollies MUST have hard water, and if you water is soft, adding marine salt mix will raise that hardness as well as the salinity in a safe, convenient, and inexpensive way.> I now have a heater and ensure that the temperature stays around 80 degrees Fahrenheit. <Thank the Gods!> I am trying to grow live plants in the tank. She hovers over the bottom of the tank and her gills are opening fairly rapidly. <Dying. This is called "the Shimmies" and indicates when Mollies are being kept chronically badly.> Also, I noticed that after a while the rocks in the water start to emit a blue dye. <No idea what this is. But GET THOSE DAMN ROCKS OUT NOW! Nothing you put in a fish tank should do this. ONLY buy aquarium-safe rocks.> I have cleaned out the rocks thinking that was the problem, but she is still showing the same symptoms. <Doubt the rocks are the key thing here, to be honest.> Could the problem be an internal parasite? <Nope; bad fishkeeping.> I was also wondering if she might be pregnant, but I don't know the signs of pregnancy. <May well be, but this isn't what's causing the problems.> Any advice you could give would be helpful! <Read a book. Please. The only way you could be keeping this fish worse is by forgetting to put water in the tank. You are doing everything wrong. I really, REALLY want you to enjoy this hobby, and even more want that poor little fish to survive. But you MUST raise your game. Short term: stop feeding the fish until you buy a NITRITE test kit and learn how to use it. Do 50% water changes daily for as long as you detect nitrite in the water. Add marine salt, not less than 3 g/l. Don't use "tonic salt" or "aquarium salt" or anything like that. You want the stuff marine fishkeepers use because ONLY that will raise the carbonate hardness along with the salinity. These perform together to make Mollies happy. Once you've done that, start saving your pennies for a bigger tank; not less than 20 gallons.> Thanks, Cara <Good luck, Neale.>

Molly Tank 1/27/08 Hi all, <Ave,> I do have a question or two about my brackish molly Tank. I was having a lot of problems trying to keep my mollies in FW so I decided to go low salinity (SG 1.005-1.008) brackish tank and keep mollies that I had (3) and eventually a few Bumblebee Gobies. <Very good.> The tank is 14 gallons with aragonite sand, ph 8.0- 8.1, Temp 82F. The tank is not cycled. It started with 3 mollies. I did acclimate them, but I think I might have taken some bad advice and did it a bit faster than would be desired, like over several hours instead of days. Both females had fry in the new brackish water, about 18 total. <Mollies can be acclimated between marine and fresh in less than an hour, so unlikely a problem here.> The problem is this: first off, there was flashing, even the new-borns, occasionally shimmies, which I had in the freshwater environment which is what eventually led me to going brackish. Later in the week twitchy behavior for my male (like a nervous twitch and then get all tense) and sometimes 1 or 2 of them would skip across the top flapping tails. <Do check water quality. Essentially, the problem with Mollies seems to be a hypersensitivity to dissolved metabolites. Not just ammonia and nitrite, but also nitrate. If you suddenly raise the salinity in a freshwater aquarium, you are placing a stress on the filter bacteria. As a rule, you can go up to about SG 1.005 without any problems, but once you go above that, the filter bacteria seem to die back or at least stop working properly. So the usual process when creating a brackish water tank from a freshwater one is to raise the salinity in stages. I'd recommend adding SG 1.005 water to the aquarium each week, replacing about 20-25% of the water in the tank. After about a month the specific gravity will be 1.005 or thereabouts. Leave things be for a couple of months. For Mollies and Bumblebee Gobies, this salinity is more than adequate for long term health. But if you did need to raise the salinity further, do it in small increments over the succeeding months, checking the ammonia and/or nitrite all the time. It's much better to choose a lower salinity without ammonia than to go the whole hog to a high salinity but have ammonia in the water because the bacteria are unhappy.> And then one fish in particular would stay at the top and gulp for a very long time. I originally had a BIO-wheel 100, which I swapped out for a BIO-wheel 150 and a Whisper 10 air-pump and air-stone. Ammonia was reading at about .25 so I did a 10% water change, lowered the temp a tad to about 80F and the water line to get more surface agitation. <Ah, almost certainly this was the issue. The filter is stressed from you taking the salinity too high, too quickly. Give it four to six weeks to re-mature, putting the minimum food into the tank and performing regular water changes. Lower the salinity to SG 1.005 to economise on salt usage, but step up the water changes in the short term at least to keep the ammonia/nitrite levels low.> This morning I decided to go out and get the babies their own tank thinking perhaps the bioload was not too good and maybe the oxygen not so good either, especially with the temp and SG. I am very new to brackish so a lot of this is new to me. <Please do read the articles on the topic here at WWM. Or my book!> Anyway, Ammonia is 0 again or at least at the lowest color on the test, but my Male molly still has the twitches and tenses up and occasionally flashes off the filter inlet tube...this is like once today though, not like once every 5 minutes like before. <Getting better, I guess...> One of the females still is piping occasionally, but not for prolonged visits, like just up, gulp gulp, down. <Mollies are distinct among the livebearers in being able to use atmospheric oxygen when the situation is bad. They gulp water from the air/water interface across the gills, extracting the dissolved oxygen. In the wild this allows them to survive in swampy environments better than other livebearers. It's a "normal" behaviour, albeit one that implies less than perfect water quality.> Shimmies at least visibly gone. SO I guess what I am asking is do you think this is a gill infestation/infection or do you think the water quality just got really bad really quick? <The latter.> Also will the fish recover if water quality, maintenance and stocking are done properly in the future? <Yes; in brackish water Mollies tend to be rather robust and durable.> Any help would be greatly appreciated. Keith <Good luck, Neale.>

Re: Molly Tank  1/26/08 Thank you for the quick reply. <Happy to help.> I have started daily water changes and am monitoring the ammonia and salinity to keep them under control. <OK.> One more question for maintenance, what test kits and water conditioners can I use...meaning, what freshwater stuff is ok to use and what must be marine? <Water conditioner is fine for freshwater/brackish/marine uses. Water chemistry test kits are normally fine in FW/BW/M though some are not; check the package. Water quality test kits are usually fine too. Medications are often fine in both, though some are not; again, check the package you have.> Currently I have freshwater Nitrite and Ph tests and an ammonia test kit that is for both SW and FW. What about FW phosphate removers, dechlor, etc or is that not an issue because the water is treated before going into the aquarium? <The nitrite test kit should be fine in brackish, and likely so too will the pH test. The issue with pH test kits is that marine aquarists want ones that are accurate across the high range (between 8 and 9) whereas freshwater aquarists want ones to use between 6 and 8. So the two types of test kits are tweaked to work best depending on what sort of tank you have. So long as your test kit measures 7.5-8.5, you're OK using it in brackish.> I am guessing low salinity like .005 is probably closer to FW than Marine, but how much of a variance does the salt add in accuracy of FW tests and possible conditioners being toxic in a Brackish tank? <As you say, not a huge impact. For the time being stick with what you have. As and when they run out or expire, switch to ones suitable for both FW and Marine, and these'll have you covered. Cheers, Neale.>

Re: Molly Tank 1/29/08 Neale, <Keith,> Thank you! Everything is settling in and the fish seem very happy/normal and less irritated. <Very good.> One last thing please: At what level does ammonia "start" to initiate the cycle and at what level should a water change be done? <Difficult to say, but in practise you never need to allow the ammonia concentration in the aquarium to reach measurable levels if there are fish in the tank. When people are cycling tanks *without* fish they can let the ammonia level go as high has 0.5-1 mg/l safely enough, but there's no real advantage given that the growth rate of the filter bacteria is limited by oxygen as much as ammonia concentration. Hence in practise when you are cycling tanks with fishes in them, you do your level best to keep the ammonia (and nitrite) as low as possible. The bacteria will get enough of both even so. Water changes during the cycling phase should be as often as possible, but as a baseline I'd suggest 25% daily for the first week or two, and after than about the same amount every 2-3 days. After week 3 or 4 you should find ammonia stays close to (or at) zero, and nitrite under 0.5 mg/l, and you can get away with two 25% water changes per week. After week 4 and certainly by week 6, the cycle should be finished and you can switch to 25-50% water changes weekly. But these are estimates: your own "mileage may vary" and you need to follow your nitrite test kit results rather than the theory.> I just saw that your book ( Brackish-Water Fishes: An Aquarist's Guide to Identification, Care & Husbandry) is available on Amazon, ordering on payday. Again, Thank you for the invaluable help. <Hope you enjoy the book!> Keith <Cheers, Neale.>

Molly - need your expert opinion, sys., hlth.    12/5/07 Hi, I love your site. I am new to all this - I have read and read and read on google and all kinds of sites about my specific questions but I am getting mixed information and partial answers, so I thought I would get your opinion on it. <Hmm... Google is efficient at finding stuff, but remember that the Internet is a mix of 50% gold and 50% garbage. If you're new to fishkeeping, you will be MUCH better off buying or borrowing a decent aquarium book, of which there are many. These will be edited and written to a higher standard than most of the stuff on the Internet.> I have a 40 gallon hex tank with a side filter / carbon filter that goes inside etc/ I have 6 small red eye tetra, 4 mollies and a female (very sweet beta) <OK, start by chucking out the carbon. Waste of money and space. Replace with some filter wool or ceramic noodles. Carbon serves no useful purpose in most freshwater aquaria. Biological filter media is always useful. Tetras and Mollies are not good tankmates; Mollies almost always do better in salty water than freshwater, whereas Tetras (for the most part) don't tolerate salt at all.> First of all I know I have totally stressed out my black molly because of moving her too much. <Oh?> Two of my females have wound up pregnant, I don't want the other fish to eat the fry. I bought one of those breeders where the mothers are up top and the babies end up going thru a slot on the bottom so they are protected. <Never, ever put a Molly in a breeding trap. She will hate you with the heat of nova. Breeding traps are really something that sounds a better idea than it actually is. Mollies are too big for them, and really so are most other livebearers. Instead, stock the tank with floating plants. Hornwort is idea. Check the plants once or twice a day, and then remove fry to a breeding trap or better still another tank for growing on.> First of all, one of them has been huge for about 4 weeks and for 4 weeks I have been saying, any day now! No fry yet and I have no clue when she is going to have them. Any signs I can watch for so I can get them out quickly with a net ? Do you have any pictures so I can see how big they are supposed to get. Maybe there are not really any signs? <One problem with Mollies is that in freshwater they often get sick, and oedema (dropsy) can look for all the world like pregnancy. Another issue is some varieties have been deliberately bred to be rounded, so it isn't obvious if they are pregnant or not. Finally, many fish will eat the fry at once. Sometimes even the mothers! So the babies can literally have a lifespan of minutes, too short a time for you to observe them.> I put her in the breeder for a about a day and noticed she seemed stressed and I felt bad because it was so small. I know mollies require lots of space to be happy. I have found very different opinions on this subject matter. <I can't think who in their right mind would be opining that Mollies are happy in breeding traps or don't need space. As I said, 50% of the Internet is garbage.> I took her out of the breeder and put her back in the tank with the others for about a week. Much better!. Then I decided to put her in my daughters tank which is bigger than the breeder but still small (it's like 2 gallon). (I don't have the extra $100 or so to set-up a new tank right now being so close to Christmas) <Floating plants... floating plants... cheap, effective...> After her being in the 2 gallon for a couple of weeks, and still no fry, I moved her back into main tank again since she seemed stressed in there. I put some plastic floating plants at the top and there are lots of holes in the ornament that all the fish can get into. <A two-gallon tank is really not going to work. For one thing the Molly will be incredibly stressed. Miscarriages under such conditions are common. Even if any babies were born, she might eat them because there's really no space for the baby fish to swim away.> Those tetras seem kind of aggressive and chase the other fish and I am worried that they will eat the fry - will they ? <As sure as God made little green apples...> Should I get rid of those ? I can find someone on craigslist to take them probably. <Yep. If you want to keep Mollies -- seriously -- and get babies, then your life will be 100 times easier if the Mollies have a spacious tank with some salt (~3-6 grammes per litre) added to the water and lots of floating plants. The Tetras are merely adding a complication.> Thanks for the information. Wendy <We do have a nice detailed article on Mollies, here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Have a read, follow the links to related articles, and good luck! Neale.>
Re: Molly - need your expert opinion12/5/07
Thank you, thank you. I appreciate your time and your very valued opinions. I let the Molly out of the breeding trap and I am going to find another home for the tetras ASAP. The word "trap" should be an indicator huh ? :-) Your awesome. Wendy <Cool. Glad we can help. Mollies are among my favourite fish, and when cared for properly EASILY fill a tank with colour and entertainment-value all by themselves. That's why I recommend people keep them alone so they don't have to make compromises to allow for their tankmates. Give the Mollies 100% of what they want, and they'll repay you handsomely! Colour, activity, sex, and babies. What more could you ask for! Cheers, Neale.>

Sick mollies, internal parasites? hello All, <Hello,> thank you for this web site, a fantastic resource. I have been reading for two days straight and am a bit overwhelmed at this point. Please forgive any chargin blunders as I am very new at the fish thing. <Ok.> we had four pot belly mollies. (2 remain, a male and a female and seem 'fairly' healthy.) and also an Oto in a 6 gallon heated Biowheel tank. 2 of the mollies died in a weeks time, 1st a male and then 5 days later a female - whom I found this morning : ( the ones that are still with us came first, about 3 months ago, the two that died came about a month later. <6 gallons too small for Mollies. Almost no chance of maintaining them for any length of time. Mollies are very intolerant of poor water quality, and it's virtually impossible for an inexperienced aquarist to keep water quality good in such a small tank. Moreover, male Mollies are somewhat aggressive, and in small tanks can become real bullies.> The remaining male is very aggressive and chased the other male around relentlessly, but I never saw any wounds on him. <Ah, there we go. Absolutely predictable. This is why you need to *read* about fish before you buy them; most problems are easily preventable.> ( I had read about the ratio being a little off which is why we didn't do too much researching when he passed away last week, very thin.. we thought it may have been stress from the aggressive male, in retrospect I feel that was wrong). <Indeed. The ratio is one male to three females for 100% success, and that will only work in a tank with sufficient space. I'd consider 20 gallons the absolute minimum for Shortfin Mollies, and 30 gallons for Sailfin Mollies.> we have done a few 20% water changes recently. every time I have taken my water to be tested they tell me the levels are all perfect. Even yesterday... <50% water changes per week are MANDATORY with Mollies because they are so intolerant of nitrate. In addition, small aquaria need generous water changes simply to remain safe.> I watch the mollies regularly and noticed white stringy pooh coming out of the (now deceased) other female molly. (which I never saw coming out of the male that died) I give cooked mashed inside of frozen peas about twice a week and also feed once a day a flake food that enhances color. <Diet is an issue with Mollies. The simplest approach is to use algae-based flake food most days. One or two days per week, don't use flake at all, and instead offer thinly sliced cucumber or strips of Sushi Nori. They'll peck away at these contentedly. It's important to understand wild Mollies feed almost entirely on algae. Meaty foods, like bloodworms, are very much treats, not staples.> She would try to eat but then just spit it back out for about a week before she died (she did not look thin when she died like the male did). at first I thought she might be constipated as she looked a little bloated. I have been reading the white stringy pooh can be a sign of internal parasites. <Depends on the fish. But to be honest, "internal parasites" is the catch-all scapegoat inexperienced fishkeepers use to cover their own failings. Internal parasites of various kinds do exist, but they're unlikely to cause the death of a fish unless the fish is otherwise unhealthy. Poor water quality, the wrong water chemistry, and so on are the main things that weaken a fish, and once weak, parasites can become problems.> her other symptoms where hiding, taking in air at the top and then on her last day shimmying. yesterday (at the advice of the LFS) I added some freshwater aquarium salt, 2 teaspoons an hour apart from each other, and some nova aqua conditioner/fish protector. she seemed to have a little relief, but didn't make it through the night. <All symptoms of poor water quality and the wrong water chemistry. Mollies simply are not beginner's fish. While some folks keep them in freshwater tanks, mortality when kept thus is very high and lots of people fail to keep them alive for more than a few months. On the other hand, in brackish water they are very hardy. Brackish water is more than a "teaspoon of salt". You use marine salt mix (NOT tonic or aquarium salt) for a start. This is because marine salt mix has both sea salt plus carbonate salts for stabilizing the pH and hardness. Ideally, Mollies need a specific gravity of 1.003 to 1.005, 6-9 grammes per litre.> the question I have is about the remaining fish, the female has been also going for air, but still interactive and eating. <It'll be dead soon.> I added the 3rd teaspoon of salt this morning as she was gasping at the top after eating. this seems to have helped and she seems better although I am noticing what looks like subtle shimmy. and is not grazing like the male is. <The "shimmying" is a disease called The Shimmies, a neurological problem caused by chronic poor health. There's no cure as such, but when transferred to brackish or marine conditions most Mollies recover. Kept in freshwater, they die.> I am considering using the Parasite Clear because of the death of the other two, but don't want to medicate unnecessarily as I have been reading how dangerous this can be to all the fish in the tank. <Pointless. Unless you can identify a disease, treating with a random medication is unhelpful. Imagine if a doctor didn't listen to you describe your symptoms, but simply gave you a handful of the first pills he found in his bag.> it sounds like an overall approach. <Nothing of the sort. The issue here is likely water quality and water chemistry. At the very least, you need nitrate less than 20 mg/l; zero ammonia and nitrite; pH around 8.0; general hardness around 15 degrees dH; and carbonate hardness at least 8 degrees KH. Ideally, the specific gravity should be at least SG 1.003.> your thoughts on this product as related to our symptoms? <No relation at all.> thanks for helping. Shellie-Rae <Move your Mollies to a brackish water aquarium not less than 20 gallons in size. Otherwise, they will die as sure as God made little green apples. Don't put freshwater community fish in there unless you know they are salt-tolerant (most aren't). Hope this helps, Neale.>
Re: sick mollies, internal parasites? update  11/13/07
thank you for your reply. I too wish I would have read more on these fish. its becoming more apparent (the more I do read) how little they know at the fish store...ugh! <Trust me Shellie-Rae, you aren't the first person to learn this the hard way. While many store owners try very hard, often some of their staff are just kids doing a Saturday job or whatever, and don't really know much more than a lay person. So while discussing things with the guys in the pet store is never a bad idea, you should compare what they say with what you read in books. And when you find a good store, cultivate your relationship with the owner. I learned a lot of the basics from good, reliable pet store owners.> so that brings us to now, I'm a beginner with little knowledge and 2 (remaining) potbelly mollies that I am smitten with, Spot a male and Dotty the female. <Mollies are among my favourite fish, so I understand your affection for them!> my female is still hanging in there she is eating although not as enthusiastically as before I noticed symptoms. I took your suggestion and switched to an algae based flake food called 8 Veggie Flake. <Good.> although the second ingredient after spiraling is fish meal? will this do for long term? <It's fine.> there is 1 tbls of fresh water (again, what they suggested at LFS) aquarium salt total for 6 gallons. <I tablespoon of salt is 3 teaspoons; each teaspoon of salt is 6 grammes. So that's 18 grammes of salt per 6 US gallons = 22 litres. Hmm... less than 1 gramme of salt per litre. Well, that's better than nothing, but I'd triple that (at least) to be honest. For complete success, I'd be aiming at 6 grammes of salt per litre, or about 0.8 ounces per US gallon. But if the water is rock hard (a high carbonate hardness, say 8 degrees KH or more) then you may be OK. By the way, you'll probably find marine salt mix cheaper in the long term. Tonic salt is overpriced for what it is. Marine salt mix can be bought in bigger boxes that last a long time.> I did a 20% change a few days ago (before I got your email) and a 30% last night. I am willing to try and go more brackish...just want to make sure I'm informed before making any more fatal mistakes... <With Mollies, adding a bit of salt makes so much difference, and using marine salt mix makes them virtually bullet-proof. The benefits are obvious and dramatic once you start keeping them thus.> Dotty seems thin to me and is also spending a considerable amount of time at the top sipping. <That's air-breathing. Mollies are exceptional among the guppy-family of fish in being able to pump a mix of air plus water across their gills. To some degree they do it now and again even under good circumstances, but when the water is too warm, too lacking in oxygen, or too dirty, they do it frequently. So it's a heads-up that something is 100% perfect. If in doubt, change some water.> what should I do next? <Keeping doing what you're doing: change the water regularly.> I have not added any meds to this tank except for 1 dose of jungle parasite food. (also added before I got the email) <OK. Won't do any harm, at least.> we are unable to accommodate with 20 gallons as suggested. <Too bad. But do keep this in the back of your mind, and any time you see a 20 gallon that fits the space and budget you have available, consider it a wise purchase.> so hefty water changes aside how can we have happy mollies here? <Yes.> thanks again for being so helpful even when it is the harsh truth! Shellie-Rae <Do enjoy your fish, and read up on them a little more so you're prepared for the ins and outs of keeping them! Cheers, Neale>

Sickly mollies   7/10/07 Hi, about a week and a half ago, one of my mollies had babies. Now, just a few days ago, my other molly had her babies. I've been watching the babies very carefully because both of the mothers were sick when they gave birth. And although I separated the babies from their mothers immediately, I was afraid they had been exposed to the bacteria too long. All of them seem to be doing pretty well, but there is one that I am concerned about. I'm afraid that I've spotted some tail rot on him. The only problem is, he is black with some white patches, so I don't know if the pieces that appear to be missing from his tail are gone, or if they are just transparent, like some of his siblings tails are. At first I thought that it might just be his coloring, but today I've noticed that he is clamping his tail a little bit. Can you please help me? I don't want to treat the tank for no reason, but I also don't want his sickness to get out of control if he is actually sick. I don't know what to do, and all of my hospital tanks are full, due to recent ich and tail/fin rot break outs. Thank you, Rebecca <Hello Rebecca. The first question is do you keep your mollies in fresh or brackish water. Mollies require hard (20 dH+), alkaline (pH 7.5-8), and preferably brackish (SG 1.005) water conditions. Failure on any of these counts tends to make them sickly. Period, end of discussion. I know people sell mollies as "good community fish" but they really aren't. So, what are the water conditions? As for treating the tank, assuming you choose the right medication and dose according to the instructions (removing carbon from the filter, of course) there's no risk to the baby fish. In fact, when you start breeding egg-laying fish, you'll discover that adding medications pre-emptively is standard practise. So in this instance, treat with a combo fungus/finrot medication. Cheers, Neale>

My golden molly is turning black...  6/12/07 Dear crew: <Hello.> I first off want to apologize for my lack of knowledge of fish completely. <Hmm... not a good start. When caring for any animal, it is always wise to read first, then buy the animal, not the other way around.> That taken care of, I bought a gold molly to keep my albino... side sucker fish company so he'd have a friend. <What's a "side sucker fish"? I'm guessing either a Plec (an armour-plated catfish) or a sucking loach Gyrinocheilus aymonieri (a minnow-like fish with a sucker mouth). Either way, appallingly bad choices for neophyte fishkeepers. Plecs grow to around 30-60 cm depending on the species very rapidly and eventually need massive tanks. Sucking loaches also get big (around 25-30 cm) but top that off by being among the nastiest-tempered fish out there. Either way, you will need a tank containing at 200 litres within even the medium term (6-12 months). If you don't have that, return them. One other thing: mollies are extremely delicate when kept in freshwater tanks, and the only sure-fire way to keep them healthy is to keep them in brackish water. Brackish water is unacceptable to both the catfish and the sucking loach. Now, if you feel the need to keep mollies in freshwater despite the fact some or all of them will get sick, you need to ensure the following: Nitrates less than 20 mg/l; pH 7.5-8.2; hardness 20 degrees GH or more. Skipping on any of these is the express route to mollies getting fungus, finrot, and the "shimmies" (a type of nerve damage disease). Don't believe me? Stop by any fish forum you like and review the questions in the Livebearers section. The number of messages about sick mollies will stagger you. I feel I say this every week, but mollies just aren't good fish for beginners and they categorically aren't community fish by the generally accepted meaning of the word. Have a read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  and some of the FAQs as well.> I've had these fish for about 3 months and all of a sudden my gold molly is turning black, starting with the tail. <Almost certainly just genetics. Assuming the fish is otherwise healthy and the skin isn't rotting or something. Mass-produced mollies are not "quality controlled" so you have no guarantee they are "pure bred" in any way. So, it's basically a case of enjoy your newly metamorphosed fish!> I've tried doing some research and I can't figure out if this is just a gold molly turning into a Dalmatian molly (do they do this?) <With quality stock, no.> or if it has some sort of problem... in which case I'd like to help. <No, nothing you can do.> Thanks! Jen <Good luck. Mollies are among my favourite aquarium fish, but they are demanding and they do need special care. It's a shame they're so widely sold, because people assume they're easy fish. But kept well, few fish combine personality, colour, and easy breeding so well. Worth sticking with, and learning about. Cheers, Neale>

Mystery Molly Ailment   9/11/06 Hi, everybody. <<Hello, Tim. Tom here.>> I have a four week old 20-gallon aquarium with 16 inches of fish, plus my unexpected delivery of four two-week-old baby mollies. All tank mates have been compatible so far. <<A more specific listing of what you have would have helped here, Tim. Mollies lean toward brackish water conditions so the word "compatible" needs to be taken rather broadly. Bettas and Goldfish require such different water conditions that they would be deemed incompatible though they might never "bother" one another in the sense of aggressiveness.>> My water parameters (temp, nitrites, nitrate, ammonia, pH, hardness) have all been within range until about a week ago, when my nitrites spiked. <<Very predictable with a new aquarium. Ammonia levels had to have spiked as well or there would be no nitrites. A reading of zero is the only acceptable level for either of these.>> I have treated since then, but my molly has come down with a baffling disease. <<Other than treating with BIO-Spira from Marineland, there's nothing readily available to hobbyists, to my knowledge, that's capable of reducing nitrite levels to acceptable levels in a short period of time, Tim. (For those of our friends outside of the United States, BIO-Spira is only available in the U.S.) Sorry for the brief "commercial", Tim. Let's go on...>> It will sit on the bottom of the tank, fins clamped, barely breathing, moving only to eat (quite well, too) and go to some more secluded spot. <<What you describe is symptomatic of poor water conditions or, what were poor conditions, that adversely affected your Molly. If she's the "Mom", the birthing process may have also taken its toll on her. Could be one, the other or a combination. Livebearers like Mollies, Platys, Swordtails and Guppies need recuperation time after the "blessed event". Frequently, they don't get this and the stress is too much for them, sad to say. The addition of aquarium salt to the tank might benefit her but without knowing what other fish you have in the tank with her, I can't recommend this with any confidence. If you have any species of Catfish like Corys or Plecos, these will not tolerate salt well.>> What in the world is wrong with it, and how do I treat it? <<Frustrating though this may be, Tim, I can't give you anything definitive to go on without more information. I've suggested what "might" be the problem(s) but don't have enough from you to go on, quite honestly. Water parameters that are "within range" is too vague a description of the conditions to know exactly what's going on in your tank. For example, nitrite levels at 0.5 ppm might be described as "within range" by some sources. To us, that's in the 'danger' zone. If an undetected ammonia spike preceded the nitrite spike that you discovered, your Molly's gill membranes may have been damaged as well.>> Is it contagious? <<Best guess (and only a 'guess')? No. 'Contagious' maladies tend to spread rather rapidly in an aquarium. I suspect that your Molly wouldn't be the only fish that you'd have issues with.>> It has no physical signs of disease. <<Not likely to if it's what I've described, Tim. If you'd write back with specifics, i.e. 'exact' water parameters, types of fish, etc., I'd like to give this problem a better "shot" than what it may appear to you like I've offered up. Tom>>
Specifics on Mystery Molly Ailment  - 09/14/06
Hi! Tim again. In your last reply, <... don't know who to send this to as you didn't copy/paste the prev. corr.> you asked for the specifics on my tank. Here goes:         pH:             7.0 consistently     Hardness:    Moderate (about 50 ppm)     Nitrite:         0.5 ppm and going down <Should be zip>     Nitrate:        20 ppm <About the upper limit...>     Ammonia:    0 ppm     Temp:          Steady at 80 degrees F     Salt:            1 tsp. to every 10 gallons <Wouldn't add or have present continuously...>     25% water changes/thorough gravel vacuumings once a week.    The tank mates are: 2 gold gouramis, 2 zebra danios, 3 mollies and the molly babies. I also do believe it was the sick one that gave birth - didn't witness it, though, so can't be sure. Plus, on the nitrite treatment: you're right. I bought something else (the only pet store we have doesn't have BIO-Spira) and it has taken a long time for small results. I had no ammonia spike afterwards; ammonia remained at zero all the way through. Thanks! <Do please send along previous correspondence with any/all email... there are a couple dozen of us here, and much email traffic. BobF>

Vertical Mollie?   8/18/06 Hi <Hi Alex, this is Jorie.> I recently bought a couple of Mollies (1 male, 1 female) and set up a 10 gallon aquarium which seemed to go really well. today I added a couple of guppies. After 1/2 hour or so I noticed that the female molly is swimming almost vertically, nose down. The male seems to be fussing around her and nuzzling her. Is anything wrong? <If you haven't already, you should test the water parameters, including ammonia, nitrite and nitrate.  How long has this tank been established and what type of filtration are you using? Has the tank fully cycled?  A bit more information would be helpful. Also, with regards to livebearers (both mollies and guppies), it is not typically a good idea to have a 1:1 male:female ratio, as the girl will usually get very harassed by the male.  Having said that, I'm not suggesting you run out and immediately buy more females - are the four fish you mention above the only ones in there?  *If* the tank is established (i.e., cycled), then I would suggest perhaps adding a couple more girls, or perhaps even swapping the male for a female, if possible.  You do realize that livebearers, especially mollies, seem to reproduce exponentially - have you figured out what you are planning on doing with the fry? Do take a look here for detailed information on all things pertaining to FW aquariums: http://www.wetwebmedia.com/FWSubWebIndex/fwsetupindex.htm > Thanks for the help, <Hope I have helped. Jorie> Alex

Black mollies dying   6/9/06 We lost our female black molly suddenly, she seemed fine then her stomach became very bloated and she died the next day. That was a couple of months ago and yesterday the same thing happened to our large male. He seemed fine, swimming and eating, he swelled up over the course of a day and was found dead this morning. please could you tell us what it could be and what we can do to prevent it happening again. It does only affect the mollies in our tank. Thank you. Lisa-Marie. <Mmm, frightening... but not uncommon. Most mollies are raised with at least some strength of salt/s in their water... Keeping them in systems with little or none, with lower pH, alkalinity often leads to the above symptoms, loss. Please read here: http://wetwebmedia.com/FWSubWebIndex/mollydisfaqs.htm and the above linked file on Molly Systems... Bob Fenner>

Thinning mollies  02-05-06 Dear WWM, <Deb> I have been noticing a strange occurrence in my 20 gallon tank. I have mainly sailfin mollies, a platy, a few tetras and a couple of horse head loaches. <The mollies are mis-mixed here. They are brackish water animals...> When I buy mollies, they appear to be healthy. After some time, they begin to completely thin out in the belly until they eventually die. This process tends to take about 4 to 6 months. What on earth am I doing wrong? <Putting them in with animals of a dissimilar water quality/nature> I feed them flakes and I add one tbsp of salt per 5 gallons of water. <Oh!> I don't know what is causing them to fade away into nothing. They never appear to have any visible problems or diseases. Please help. Thanks, Deborah Ward <Could be just the initial health of the livestock... but I suspect that the water is not "salty enough" (see WWM, fishbase.org re)... and your other listed livestock don't "like" this much salt... Bob Fenner>

FW environmental disease >Hi my names Cora I've been doing tanks for years and until recently I've never had any trouble.   >>Hello Cora, Marina here. >A lady contacted me because I take in unwanted fish.  Due to her moving from Ohio to Maryland she needed a home for her fish (black mollies).  She told me to come get tank and all so I did.  Needless to say when I got there the water was black! >>Ack!  (And uh oh.) >I felt bad for the fish caught them drained the tank and loaded it all up into my car and brought it home.  I gave that tank a good cleaning no chemicals used of course and used water from my 55 gallon tank that had just had a partial water change the night before. >>Personal experience: mistake #1.  (Groaning, because I learned my mistake with a customer's fish.) >I let the fish float for 15 minutes and then released them.  Needless to say a little while later I notice the fish were starting to act really funny.  I checked the temperature it was a little high so I lowered it the water then started to get a milky white. >>Free floating bacteria found plenty of nutrients--new tank syndrome. >And the fish were still acting funny and 2 died.  I pulled the fish from that tank and floated them in my 55 gallon released them and they did fine. >>I wouldn't have done that, but you saved the rest.  My concern is the very real risk to your well-established tank by introducing the new fishes with no quarantine whatsoever, coming out of a foul-looking (but apparently healthy) tank. >I left them in the 55 over night and by morning the other tank had turned clear (no chemicals were used at any point of my set up ) so I put in 2 clown loaches and a few mollies needless to say they started to fly through the tank and act as though they were going to die I immediately put them back into my 55 and now they are fine but the other tank is milky white again.  Can you give me any ideas as to what might be going on?  I've worked in pet shops and have had tanks for years and never experienced anything to this effect.  Any information would be greatly appreciated!   Totally Confused,    Cora                                                                 >>Again, this sounds like new tank syndrome, though it usually takes a few hours for the bacteria to get a good foothold.  You never mentioned the size of this new tank, and I cannot recommend adding so many fish so quickly unless we're talking about a 75 gallon or larger set up.  At this point you MUST remove everything from the tank and fill it with water, then add bleach at a ratio of 1Cup/5 gallons.  Let it sit like this a few hours, then drain and allow to dry.  I would do this with everything that was associated with that tank as well.  If you're very worried about the tank, do this procedure twice, and then when ready to set it up again start with feeder gups first.  Beyond that it's difficult to say what to do, I'm assuming you know to match temperature and pH when transferring fishes, and to never introduce water from one system into another.  I hope this has helped answer your questions.  Best of luck with your new wards, Marina 
Re: Help!!!!!!
>Hi Marina >>Hello Cora. >Thanks for responding to my e-mail I did as you suggested and the fish are doing great the tank is only a 20 high so dividing the fish up was needed.  Needless to say I now have 3 tanks set up for fish lol but who cares I love them and enjoy watching them more than the TV. >>Indeed.  Did you know that you can actually acclimate the mollies to full saltwater?  Glad to hear they're doing well, too.  Marina

Bilateral Popeye/Color Change in Mollies I have a tank of marble mollies...some are babies of the originals.  A couple of days ago I noticed that one of the younger mollies had both eyes popped out similar to a telescope goldfish.  She seemed alright otherwise, but since has taken to hanging out at the top of the tank and seems to be blind, can't seem to see food too well.  Also looks thin.  I'm wondering if I have a case of mycobacteriosis.  This is scary because I read that humans can contract it from fish.  What should I do for her? <This conditions sounds like it could have been brought on by poor water quality or stress.  Is your water hard, alkaline, and slightly salty, about 1.004 on a hydrometer.  Have your water tested to be sure everything in in line.  If you are not adding salt already, frequent water changes and the addition of salt should help her. I doubt it is mycobacterium marinum... AKA Fish TB (tuberculosis), but be cautious just the same. http://www.wetwebmedia.com/Wound.htm  > My other problem is that a black/gold molly I have which was more black than gold has changed color so that now she is almost completely gold.  She is almost one year old.  Do mollies change color or is this some disease? <It is perfectly normal for them to change color.  Best Regards,  Gage> Thank you for you help.

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