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FAQs on the Molly Health/Disease 6

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

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

Mollies troubles 11/10/09
I have 14 tanks ranging from 5 to 55 gallons mostly Acrylic and mostly containing fresh water native species. Bluegill, Blue spots, Orange spots, Longears with a couple of tanks of Rosies.
<Sounds fun! Not a big fan of 5-gallon tanks so far as fish are concerned,
but a 55-gallon tank full of native fish would be a treat!>
A week ago I bought 8 Mollie from a petstore to put in a 30 gallon SeaClear eclipse tank that I had cycled with 3 (healthy) goldfish. The tank has the specified amount of Aquarium salt
<By what do you mean "specified amount"? And is this plain vanilla aquarium salt, or actual marine mix?
Let's be clear on this: Mollies do best in hard, basic, slightly saline water. Aquarium salt does little/nothing about hardness and pH, so if you have soft water, adding aquarium salt merely turns it into salty soft water. Marine salt mix contains mineral salts that raise pH and hardness, so works great with Mollies. I recommend between 5-9 grammes per litre, depending on how hard your water is and how much nitrate there is in the water. In soft water, or water with more than a trace of nitrate, use higher amounts (sodium chloride detoxifies nitrate, and this is very beneficial to Mollies which are super-sensitive to nitrate).>
and I added a couple of very small well washed seashells as per advice from a book I have. I test the tank every other day and it has remained consistent. it has a 50 gallon HOB filter, a 30 gallon air pump with 7 inch wands at each end of the tank and a Jager 100 watt heater. The tank temp is steady at 78 degrees, the PH is 7.5 and the water is toward the alkaline side. The nitrates are fine.
<As in zero?>
I bought 2 silver Lyretails, 2 gold Lyretails, 2 Dalmatian Lyretails and 2 regular Black Mollies. They came out of 4 different tanks at the pet store.
I requested all females. By evening I knew one of the Gold Lyretails was sick. It went to the top of the tank and there it stayed.
<Do review temperature (which should be fairly high, 25-30 C), pH (which should be stable and around 7.5 to 8), and hardness (which should be at least 15 degrees dH). Salinity is something there are endless arguments over, but suffice it to say that Mollies *always* do well in slightly brackish water, even if they *sometimes* do fine in freshwater. This is especially true when water conditions are less than perfect in other regards. Use marine salt mix (plain aquarium salt is a false economy) and dose at 5 to 9 grammes per litre (SG 1.002 to 1.005 at 25 degrees C). I'm using metric units here because that's what I learned at university doing marine biology. It's an especially convenient approach too since one level teaspoon is about 6 grammes, so adding one level teaspoon per litre is a very easy approach to take if you're aiming for SG 1.003 at 25 C. But if you want to use Imperial units and compare them against changes in water temperature, you can download Brack Calc from my web site and make the conversions yourself. What you'll quickly discover is these "teaspoon per gallon" amounts often mentioned among aquarists are hopelessly low.>
The next morning it was dead on the bottom I took it back to the petstore only to discover that the tank it had come from now contained another dead Gold Lyretail as well. This being the case I opted for an exchange of another Dalmatian. The salesperson at the petstore gave me a hard time insisting that they needed a water sample other that the one the dead fish was in but relented and gave me the replacement. At this point I now have a bag in my refrigerator with 1 black Molly, the second gold Lyretail, & one of the silver Mollies. I have one of the original Dalmatians in a hospital tank and don't know if it is going to survive or not. I now know that you should NEVER put new fish from different tanks in the same tank. The Gold Lyretail infected the other fish and at this point I may well lose them all.
<Honestly don't think this is anything contagious. Yes, Mollies can come down with certain infectious diseases like Ick and Camallanus worms, but most Mollies die because of environmental issues. They are NOT community fish and they are NOT easy to keep and they are ARGUABLY NOT even freshwater fish (at least, fish for freshwater aquaria). The odd thing is that they're common as anything in freshwater habitats, but for whatever reason they do not do consistently well in freshwater aquaria. Various factors have been suggested for this; read here:
By default, Mollies should be kept in slightly brackish conditions. They don't need a lot of marine salt mix, so keeping them thus is inexpensive and easier than messing about with pH and hardness levels using other techniques. Many plants will thrive in such conditions, so such tanks aren't difficult to decorate. All things considered, keeping Mollies in a slightly brackish aquarium is a "no-brainer".>
My only question at this point has to do with aggression.
<Yes, they are aggressive.>
All of these fish were supposed to be female but the larger Dalmatian that is still in the 30 gallon SeaClear consistently attacks the remaining Silver Molly and the other Dalmatian (the replacement for the Gold Lyretail} which has the regular tail. It ignores the smaller Black Molly.
Is this normal behavior for a female fish or is it more than likely a male.
<Generally males are aggressive to some degree. Keep two or more females per male. They ignore species or variety differences, and a male Molly will chase any female Molly in range: Black Molly, Balloon Molly, Sailfin Molly, whatever...>
It is the largest fish of the 8, is fat and round and looking at its fins appears to be a female but I'm no expert.
<Should be easy to tell. Males have a crooked, tube-like anal fin very different to the triangular anal fin of the females. Females tend to be bigger and somewhat rounder as well.>
At this point I am beginning to feel I have been mislead about Mollies.
<Almost certainly the case. But "mislead" is perhaps not the right word here. Every aquarium book written will state in no uncertain terms that Mollies are tricky fish that do best in slightly brackish conditions. The fact people are told by retailers that they're community fish that do fine in freshwater tanks says more about being cautious about salespeople tell you than anything else. I wouldn't trust a sales clerk to recommend me a pair of trousers or a new car, and neither would I trust them on a particular fish being suitable for my home aquarium.>
So far they are 10 times more difficult than my Sunfish (which are supposed to be difficult) from every standpoint.
<I'd agree with this, and have often made the point here that Mollies aren't easy fish.>
I was lead to believe Mollies are peaceful and easy to care for. I have had a wild caught (with a hook no less) male bluegill for 6 months now in a 55 gallon tank (moving him to a 120 because he is getting to big to turn around in the 55) that eats out of my hand and is healthier that I am. I have raised Blue Spots and Orange spots from fry and not lost a one while these Mollies are dropping like flies and I DO take care of my Tanks. I am disabled, at home 24 seven and monitor them almost hourly.
<If you don't already have "North American Native Fishes for the Home Aquarium" by David Schleser, you really owe it to yourself to track down a copy. Besides covering lots of material I suspect you'll enjoy, it includes details on maintaining the North American species of Molly as well. So you'd find that part of the book very useful. You can mail-order wild Poecilia latipinna from biological supply houses, and these native species would probably appeal to you greatly. They're bigger and very impressive animals, even though (thankfully, in my opinion) they lack the bright colours of farmed fish.>
<Cheers, Neale.>
Re: Molly troubles 11/11/09

Thanks for the FASSSST response it was really appreciated!
<Happy to help.>
The 5 gallon tank is home to Daphnia, I have 2 10 gallon glass tanks 1 is a hospital tank and the other is a fry tank. As for the specified amount of salt I added 1 teaspoon per gallon & Nitrate is ZERO.
<One teaspoon of tonic/aquarium salt per gallon isn't enough. Do read my message, and understand why you're adding salt. Sodium chloride by itself has some value in detoxifying nitrite and nitrate, but it doesn't raise pH and hardness. Marine salt mix at the dose stated, roughly one teaspoon (6 grammes) per litre (0.26 US gal.) will raise hardness, carbonate hardness, and pH very effectively. While some people try to keep Mollies with less salt, or using just tonic/aquarium salt, the bottom line is they often don't do well under such conditions, so I find that a bit of a pointless approach. Much better to take Mollies for what they are, and provide conditions that suit them consistently well.>
I have read that crushed coral added to the substrate is beneficial and I do have several large pieces of coral that came out of a saltwater tank, should I follow this advise and add it or not?
<Adding crushed coral in an undergravel filter will help harden the water and raise the pH. Simply dumping some crushed coral into a tank without an undergravel filter will have little effect. Think about how this works.
Crushed coral dissolves into water that is drawn past it. In an system with an undergravel filter, there is a constant flow of water, so the coral and the water are constantly reacting with each other. In a tank without an undergravel filter, only the very top layer of substrate meets a moving flow of water; once you get a millimetre or two into the substrate, water flow slows down to practically zero. Hence the amount of reaction between the water and the crushed coral is tiny. If you don't have an undergravel filter, the better approach is to put the crushed coral in a media bag, and throw that into one of the compartments in an canister filter. If that isn't an option, adding either marine salt mix or a Rift Valley salt mix (if you don't want to raise salinity) is the best way forward. Do read here:
I have ordered the book you recommended and can't wait to get it.
Also as to the wild native species could you be a bit more specific about where I might find them
<This isn't a recommendation by any means, but one of the shops I have bookmarked is Sachs Aquaculture, here:
If you look at their Freshwater and Brackish water vertebrates pages, they have a bunch of cool livebearers and killifish that might appeal. I'm sure a little time spent on Google will reveal other, similar retailers. Clubs like the American Livebearer Association might also be good sources of information with regard to where native livebearers might be purchased.>
The bright colors don't mean a thing to me.
<I guessed as much, and I suspect you'll enjoy the book I mentioned as well as some of the other species you'll read about in there. Coldwater fishkeeping is a much neglected part of the hobby.>
If it did I wouldn't have so many Sunfish some of which are pretty plain Jane but I really like their "personalities."
<As do I.>
I may have missed it but is it common for the female Dalmatian Molly to be so mean?
<Not common, but happens. Keeping in bigger groups should help, though Bob often recommends taking aggressive fish out of the tank for a few hours, and then returning it. With any luck, that'll "reset" the hierarchy, and the bully won't be so mean.>
I am about ready to give her away (with the info of course that she needs to be isolated for two reasons)
Thanks again
<Cheers, Neale.>
Re: Mollies troubles -- 11/12/09

As I am disabled and don't drive anymore I have to wait until someone can take me anywhere to buy Aquarium items or order via the internet. I have a new unopened bottle of Seachem Marine Buffer is this of any use for my Molly tank?
<Certainly can be used. I'd start with about a half dose though, and see how things go. That should stabilise the pH between 7.6 and 8.0, which would be an ideal range for Mollies.>
It is written on the front that it safely raises & maintains ph to 8.3 and that even if more than the prescribed dosage is added it will not raise the ph above 8.3.
<This is indeed how buffers work.>
It also states that the prescribed dose will raise the alkalinity by about 1 meg/L. I realize this product is for a saltwater Aquarium so this is probably a stupid question but I have the stuff so would like to know if I can use it to advantage for my Mollies or if it would be harmful or useless.
<Can be used in freshwater and brackish water tanks safely. Make any water chemistry changes gradual though. I'd work out how much you need in millilitres or drops or whatever, and add one-quarter that amount on day 1, another quarter on day 2, and so on. This will allow your fish and the filter bacteria time to adjust. You can also look out for any unusual behaviours that might suggest stress.>
Thanks Again for you help.
<Cheers, Neale.>

Re: Molly Spinning, Upside Down Swimming, Exophthalmia & Other Bizarre Symptoms, 10/25/09
I'm checking water before every change to see if it has gotten bad.
I'm using an API liquid/test tube kit for ammonia and a Jungle Labs Quick Dip strip for nitrates, nitrites, GH, chlorine, KH, pH.
<I'm not a fan of the dip strips but they are probably fine here.>
Everything looks fine, definitely no ammonia problems. If it has changed at all, it is not discernible - still looks like 0 ppm.
Nitrites are still 0 and Nitrates are <20. A small amount of algae has begun to grow again. I'm not sure he's eating but then he's probably not producing waste. I have not vacuumed gravel (too stressful). I guess with only one fish and very little food, water has managed to stay okay. Temp is about 77-78 degrees.
Is it possible there are other things in the water that would (over 8 months) cause problems and then, seemingly all of a sudden, sicken the Molly and cause all of those strange symptoms - I'm mean corkscrew and upside down swimming was pretty bizarre to me?
<Well, in captivity mollies do pretty poorly in fresh water, but are nearly bullet proof in brackish, so that may be a partial factor here.>
I only test for the basics. I use well water and "spring" water in just about equal parts.
Our tap water is softened so the readings are: GH - Very Soft, KH - High, and pH - Alkaline. Our well water is: GH - Very Hard, KH - High, and pH - Alkaline. I was buying "spring" water to drink and it read:
GH - Very Soft, KH - Low, pH - Acidic. I gathered an approximate combination of well and "spring" water, about equal parts or a little more spring, would be about right for livebearers. I expected a moderate level of bi-carbonates and carbonates and the right GH and KH and pH. I seem to remember reading that my fish would be okay with a pH of 7.5.
<For the most part live bears like harder water with a bit higher pH, but 7.5 is generally acceptable. Sounds like your tap water may be perfect alone for livebearers.>
I always added water conditioner (no chlorine, but thought it wouldn't hurt) and aquarium salt pretty much as a "tonic"; didn't really realize at the time that Mollies like brackish water.
<I would probably forget about the aquarium salt, not really doing anything here.>
Indeed my water has been very stable over the months. I got ever so slight white, crusty build up on the filter intake. And I did get a slight brown algae growth each week. I would brush sides of tank at water change time. I changed the carbon filter about every 4 weeks.
The well water is very hard. I'm told there is a great deal of limestone in this area, but I've never heard that there are other troubling (to humans anyway) hard things. I don't know if we will continue fish keeping but I am curious about further tests that can be done on water (especially since that seems to be the biggest issue - actually I'm not sure if it's water that's the problem or changing the water that's the problem - I'll just have you know that I was diligent, every week whether I liked it or not!).
<I think ultimately the medications proved worst than the cure, I'm thinking that the current symptoms are likely the result of the chemical combinations.>
Are there other test
kits that would give better info. or would a one time test of the well water answer that question?
<Not really, you hit most all the tests available that would be relevant here.>
I just noticed I'm writing past tense - but he is still hanging in there. I guess I just can't help but think the poor Platy is doomed.
Can I just tell you that this is so frustrating? I'll keep doing water changes but the only reason it's not overwhelmingly tempting to intervene and do chemotherapy is that I don't know what to give him because I can't diagnose what's wrong.
Meg Siira
<Given good water quality fish can be surprisingly resilient, and what I would do here. A little Methylene blue may help here, but I would not try anything stronger. Best bet here in my opinion is to maintain the water quality, try to get the fish to eat, and hope for the best.>
Re: Molly Spinning, Upside Down Swimming, Exophthalmia & Other Bizarre Symptoms 10/25/2009

The Platy died as expected. Thanks for your input. Even "good" water doesn't mean your fish will be healthy and disease free. A tough lesson after diligently doing all the things necessary to get the water and keep the water in the best condition possible.
Meg Siira
<Sorry to hear, better luck in the future.>

Molly Spinning, Upside Down Swimming, Exophthalmia & Other Bizarre Symptoms 10/21/09
Here are some stats of my aquarium:
10 gal tank

ammonia 0
nitrite 0
nitrate < 20
about 8 months old
pH 7.2-7.8
GH Hard
KH about 150 - 180
weekly water changes of about 20-30% conditioner and aquarium salt added to water used in changes gravel vacuum every other water change water readings after initial cycling have been very stable except for nitrite which was initially 0 then gradually showed slightly pink (<20)only one black molly and one red wag platy (only 3 fish to start but one female died after birthing)
<Ultimately this tank is too small to keep mollies long term, which also do best in brackish conditions in captivity. In fact in brackish water mollies are almost indestructible.>
My question involves disease (no big surprise). Molly's tail looked "thin", like some of the tissue had come off; it was probably like this when purchased; went unnoticed until dorsal fin got a split down the middle; treated with Victoria green, Acriflavine (Fungus Cure), one dose, and Minocycline (Maracyn II) and erythromycin (Maracyn), one five day treatment of both. Fin grew back together from bottom up; tail somewhat better; no other noticeable symptoms. Platy had no symptoms. Three months later, noticed about two weeks of Molly darting at the top of tank, then same thing with his tail and dorsal. Intended to give same treatment but failed to give Victoria green and Acriflavine; gave only Minocycline and erythromycin. Fifth day of treatment, dorsal fin growing back together, tail looking a bit better. First day after treatment, Molly began this series of symptoms in chronological order: swimming fast, up and down, then spinning while swimming, corkscrew fashion, still trying to eat, no signs of normal bowels movements, then curvature in spine, then exophthalmia beginning, then a little difficulty in getting to top, not eating, then curvature seemed to go away, then swimming upside down solely, then listing but swimming more upright with some spinning, gulping, fins becoming ragged, exophthalmia severe in both eyes, then lying on side on gravel, then mouth protruding (or insides protruding out). No signs during this time of any fungus, external parasites. But since common things are common, I did the following in this order (obviously at first signs of illness): checked water, temp, filter - all things seemed normal, fed shelled peas and blanched romaine, removed filter media, gave Victoria green and Acriflavine (Fungus Cure), one dose, then Praziquantel, Diflubenzuron, Metronidazole, Acriflavine (Parasite Clear) one dose, then later started Minocycline (Maracyn II) treatment. Only about 24 hours between medications. I realize I could have killed the Molly with medication, but he was really bad off, and I was starting to feel even more helpless. I guess I expected 12 -24 hours of treatment to make some difference if I was using the correct meds.
Anyway, the whole thing from the fast swimming forward took about 6 days, then he died.
<Could be a reaction to the medications, could be "Whirling disease", an infection caused by the parasite Myxobolus, especially if you feed your fish Tubifex worms. First guess would be water quality and reaction to the various medications.>
Now the Platy is shimmying, and may have a few other subtle changes in behavior. Obviously there are still medications in the water, probably all of the above mentioned. The water parameters are still okay but I suspect the biological filter may be affected soon. I guess different fishes mean different symptoms but surely the Platy is being affected by exactly the same culprit. So, my questions are: 1) what is sickening my fish and should I proceed with Maracyn II treatment and/or something else
<I would stop all treatments at this point and do lots of water changes and see if that helps.>
and 2) what should I do about the biological filter - add a product or can I recycle an existing tank
<Allow it to recycle.>
and 3) what other tests are available for water, meaning what other things could be in the water that would negatively affect the fish over 8 months that I can test for (since water quality is noted as being the most likely cause of problems)?
<My first guess is the Victoria Green, aka Malachite Green, pretty toxic stuff. Combined with the other medications it could do a real number on the fish.>
Although I'm beginning to feel that a hobby that involves periodic death is not for me, I must do what I can for this remaining fish. (I also realize he doesn't want to be alone but until he is better he's going solo).
<Best move, more fish just complicate things. To be honest with mollies and Platies to a lesser degree, first thing to do is add a bit of marine salt, brackish conditions seem to do marvels for these fish in captivity.>
Sorry for such a long message. Thank you for your time.
M. Siira
Re: Molly Spinning, Upside Down Swimming, Exophthalmia & Other Bizarre Symptoms 10/22/09

Hi Chris,
Thanks for the information. I actually had fed them a few blood worms.
<Store bought frozen or freeze-dried blood worms are generally very safe, it is Tubifex worms that should be avoided due to their ability to transfer disease.>
The Molly was the eager, and therefore, fast eater. I accidentally let about 7-8 worms get in the tank, which looks like such a small amount, but I didn't feed them the worms often and usually just 2 or so per
fish (in place of regular food).
<Perfectly fine, my mollies eat blood worms regularly.>
The Molly probably ate them all or most (which is why I thought of constipation and gave veggies).
<Actually blood worms are pretty good at preventing constipation.>
But I've had this food for the whole time I've had the tank and it has never seemed to affect them negatively. Is it possible, that this food contained a "bad bug"? It is Hikari Bio-Pure FD "100% Pure Freeze Dried" blood worms with vitamins.
<Unlikely, blood worms are very safe and not carriers of disease as Tubifex can be. I think we are dealing with reactions to medications here.>
M. Siira
Re: Molly Spinning, Upside Down Swimming, Exophthalmia & Other Bizarre Symptoms 10/24/09

Hi Chris,
Thanks again.
I stopped the meds when you recommended. The shimmying in the Platy stopped, but then he began staying very still, sitting on the gravel. His tail and dorsal are changing, black near the body (normally black - he's a Red Wag Platy), then brownish as it moves outward, and then pale, almost clear and slightly frayed on the
outermost edges. After ceasing meds, I put filter in and increased water changes to 20% every 12 hours or so (water parameters are still good).
<Are you sure? Sounds like ammonia poisoning is what is possibly happening here.>

Now, he may be moving a bit more, tail and fins still look unhealthy, and his eyes look like they are clouding over and may be protruding slightly. I'm not sure, but it looks like he may be bumping into the plants and sides of the tank.
Any more suggestions?
Meg Siira
<Keep up the water changes and run some activated carbon. Double-check you water parameters because it sounds like there may be a problem there,>

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.>

Mollies sick, can't figure out what the problem might be. -- 08/04/09
Hi and thanks in advance for your help. We have had three Sailfin mollies for several months (1 M and 2 F). They have been terrific pets and are usually very energetic. However a few days ago we noticed that our male and youngest female have been acting very sluggish, almost tired. the male has been found hanging upside-down in a plant twice and both have been spending a lot of time resting on the bottom of the tank. Suspecting that it was a water quality issue, we tested for Ammonia, Nitrites, and Nitrates and found 0 Ammonia, 0 Nitrites, and Nitrates came in between 10 and 15 ppm. We did a 10 gal. water change anyway (29 gal tank) to make sure the water conditions weren't the problem. Otherwise the conditions in the tank should also be as favorable as they can for mollies in a freshwater aquarium. Alkalinity is over 8.0 and GH is 20 dH. Even after the water was changed their behavior remained the same. We moved the two mollies into a quarantine tank with higher salt content until we can figure out what is going on. They are both still eating, and they both seem to be moving around a bit more, but they are still not right. Any ideas as to what the issue could be? Other aquarium inhabitants include a handful of Cardinal tetras and Rummynose tetras, two Platies, two Chinese algae eaters, and one male Swordtail (our two females both passed away after pregnancies).
Mike & Kari
<Hello Mike and Kari. The reality is that Mollies often don't do well in freshwater tanks, period, end of discussion. So assuming you have good water quality, the right temperature (a little on the warm side, around 26-28 C), and you're offering them a greens-based diet, then they should be in good health. The lack of brackish water conditions is really all that's left.
I don't recommend Mollies as community fish, and don't advise people to buy them except in situations where creating brackish water conditions is an option. Cheers, Neale.>

2 mollies-one sick the other pregnant 7/9/09
Hi, I've been reading all your comments on mollies but couldn't find the answer I was looking for.
<Oh? Well, let's see...>
I have two mollies, one black and one orange. I'm sorry I don't know what kind exactly, just that the black is male and the orange is female and pregnant for the second time. We bought them 28 days ago and the first night we had them, she gave birth to 7-10 babies. We found them in the morning and I took the male out because he was chasing one.
<Keep more adult females than males; as I'm sure you read here at WWM as well as in most any aquarium book, you should buy one male to each two (or more) females, otherwise the females will be harassed by the males. Males are "programmed" to constantly try and mate with anything, and if there's only a single female, she'll be constantly chased, nipped and inseminated, whether she wants this or not.>
My husband crushed some flakes for them and one was going up and eating, so I thought they would be okay. The momma molly was relaxed now that the male was out. She was swimming all over the place before I took him out.
After work, I saw that the babies had all died as they were all on the bottom of the aquarium. I know now that the new water must have been the cause. The two mollies are in a 10 gallon tank,
<Far, far too small for Mollies. You need at least a 20 gallon "long" tank and realistically 30 gallons.>
with no chlorine (we have a well), good ph steady at 7 and low alkalinity.
<Nothing "good" about this; Mollies need hard, alkaline water, preferably with a bit of marine salt mix added, since they do better in brackish water. Aim for pH 7.5 to 8, 15+ degrees dH, a temperature of 26-28 C, and around 6-9 grammes of marine salt mix added per litre of water. Do all these things, and keep them in a bigger tank, and you should find Mollies quite easy to keep.>
I have a mini Penguin Bio-wheel filter system. I did a 25% change of the water three days ago. The fish were doing well until yesterday when the black molly started going up a lot and "catching his breath".
<Bad sign.>
Now he stays on the bottom on his side, moving a little because he changes places but looks dead (he's still breathing).
<Very bad.>
I think we fed them too much lately, because the female being pregnant, is always going up to see if there's food as soon as she sees us close to the aquarium. My husband said that they should have more food because of her reaction. We were feeding once a day in the morning and the last two days, we have been giving food in the morning and at night. Also, they might be stressed; I wanted to separate the male from the female before she has her babies, so I took him out, and put him in a fishbowl, with some of the water from the aquarium.
<Argh! No, no, no... moving fish about, even if your intentions were good, will cause problems of all kinds. For one thing, Mollies are stressed by poor water quality and low temperatures, both problems with bowls. For reasons too tedious to recount yet again, fish bowls are useless and totally unsuitable for keeping fish in.>
As soon as he was out, the female started to look for him and was swimming all over the aquarium.
<No, she wasn't looking for him.>
I thought she would calm down after a few minutes but she didn't. I didn't want to stress her so I put him back. She calm down right after she found him and was following his every move for a while. It was funny to see.
<I think you're anthropomorphising here.>
He kept to the bottom and hide in the plants (plastic by the way). I was wondering if he was sick and if he would get better soon or should I take him out and quarantine. If so, what do I do about my female who can't live without him? I just (today) added a tablespoon of marine salt because I did that the first time I put them in a month ago. I read that the salt might help. I have fungal meds but do not think it is fungus because he has no white stuff on him. Could it be he just ate too much and will be better in a couple of days?
We will go back to feeding once a day but tomorrow they are not getting any food. Is this bad for the pregnant female? We plan on separating the two mollies from the fry as soon as they are born by putting a Plexiglas with tiny wholes in it, in the middle of the aquarium. Is this good? I'm sorry for the long message but I wanted to give as much details as possible to anyone with a similar problem as mine. We are new to mollies but did have a couple of goldfish and a sucker a few years ago, at our first house. (We didn't have good water at that place.)
<Goldfish and "sucker fish" (by which you presumably mean a Pterygoplichthys catfish of some sort) aren't compatible, and if they died, given how hardy they are, I sincerely doubt it was the fact the water was bad. Do please read about what fish need before buying them; your experiences here with Mollies are all avoidable and absolutely classic mistakes that people do when they haven't read a darn thing about them.
While I'm happy to help, this is like the third sick Molly question of the day, and there's another in the inbox still to be done. So try reading, and then act accordingly:
Hope this helps.>
Anyway, thanks for your help! Nicole
<Cheers, Neale.>

Very Sick Black Molly... 7/9/09
I've heard good things about your site and it has very helpful advice, so I was hoping maybe I'd find help here.
<Fire away.>
I have a 20 gal. tank occupied by the fry (around a year old?) of one of my past mollies. There aren't more then ten in the tank. Recently my sister noticed one of the black mollies, a female (if it matters) has some sort of bubble-like protrusion coming out of its side. The bubble is mostly clear, with some pink in it. It actually almost looks to be coming out of the anus, or somewhere near there, like maybe some of its organs are leaking out (can this happen?).
<Certainly the area around the vent can become prolapsed, yes, and this is usually not treatable directly. If the fish is otherwise healthy and eating, the treating with a systemic antibiotics such as Maracyn may help fix the bacterial infection that caused the prolapse, and the addition of Epsom salt at 2-3 teaspoons per US gallon can relieve the swelling a bit (but by itself it isn't a treatment!). Sometimes Protozoans are to blame, in which case something like Flagyl (Metronidazole) will be needed. Since this also treats some bacteria, you might prefer to use this one first, and see what happens. Otherwise, if treatment doesn't help or isn't possible, euthanise the fish:
All the other fish are fine, are sporting no such bubbles, and are eating normally, etc. I looked everywhere and found nothing on the internet that sounds similar to this, and every time I found someone mentioning bubbles on their mollies everyone assured them it was Ick. I've treated Ick, and this is not Ick. Could it have something to do with the fact that these mollies are all breeding rather young?
<Probably not.>
We have nowhere else to put them and can't stop them from breeding.
Recently we removed all the fry we could (and placed them in some of our other tanks) to reduce the population. I once knew a woman (a former neighbor of mine, quite a while back) who had so many children so close together that her uterus literally fell out. Could this happen to a molly?
<Probably not.>
Or is it something water-related? I could test my water if you'd like to know the results.
<Most fish health problems are indeed water quality/chemistry related, so this info is always helpful. Just to recap, Mollies need hard, alkaline water with a high temperature and preferably some marine salt mix added; aim for a temperature of 26-28 C, pH 7.5-8, 15+ degrees dH, and about 6-9 grammes of marine salt mix added per litre.
Nitrate is particularly toxic to mollies, so apart from the usual 0 ammonia and 0 nitrite, under freshwater conditions at least, you want nitrate levels of less than 20 mg/l.>
I just find it odd that both our white and black mollies had fry and yet only the black ones seem to be dying. The black mother died a few weeks after we bought her, but the white mother lived for a few years. Do fish pass things like this on genetically (i.e. health problems, weaknesses)?
That being said, I've never seen anything like this before (but I have only been a fish owner for a little over two years). One more thing, if you'd like I could get a picture of the fish (I'd just have to shrink it down a bit, our camera takes huge pictures).
<Please feel free to send along such a photo.>
And if you require any other info, please let me know and I'll be happy to send it right along. Thanks so much for reading! We really love our fish!
<Good to hear!>
Brynn B.
<Cheers, Neale.>
Re: Very Sick Black Molly... (RMF? Ever seen this type of prolapsed vent on a Molly?)<<No.>>
Hello again,
I looked into the tank and found my molly dead a few minutes ago (which I pretty much expected), but I included a picture of her body nonetheless, just in case you could tell me any more about the protrusion and maybe help
me prevent my other fish from getting sick.
<Hmm... very odd. Doesn't look at all familiar to me, and seems a bit long to be a simple prolapsed anus or uterus. I have seen somewhat similar problems with another livebearer, a halfbeak, but the swelling was a large,
roughly spherical mass rather than a tube. There are a couple of photos on an article I wrote for Fish Channel, here:
(RMF, would be happy to send similar if you'd like to add to this page directly.)
<<Please do. RMF>>
In this case, the swelling was caused by some sort of problem with the developing embryos, and after dissection the dead embryos were quite obviously trapped behind the tumour-like mass, as you can see on the second
Is this contagious?
<Very unlikely; however, female livebearers are sensitive to stress, and while Mollies are not so commonly stressed as, say, pregnant Halfbeaks or Stingrays, things like miscarriages are far from unknown. This underlines
the importance of providing optimal conditions, despite livebearers being sold as "easy fish".>
Or will keeping my water quality higher in the future prevent seeing this again?
<Good water quality will of course ensure your fish remain healthier, across the board.>
Should I still treat the water with anything in case some fish have it but aren't showing signs yet? Or will I be able to tell if others have it?
(They're all eating/swimming/acting normally). Thanks loads for your help and quick response!
<Always happy to offer an opinion.>
Brynn B.
<Cheers, Neale.>

Ich Advice, mollies, more  - 06/05/09
Hi There,
I have been reading your site very diligently over the past two days as we realized two of our black mollies have ich. The information you have provided and the q/a section has been very helpful. I am sure every tank, like every fish has a different story and set of issues :-)
<As does every individual>
In our tank we have 4- 2 yr old silver mollies (not even an 1�), 3 large red Platies, 5 of their off spring and then ~10 of their off spring (3 generations), also 2 pop belly mollies, 3 black mollies, two (heckle and
jeckle) yellow mollies, 3 baby swordtails, one beautiful 5� rainbow shark
<El rey>
and ~15 more tiny babies of a mix (we thing black and yellow). Our tank has been very �busy� as of late.
Anyways our tank heater failed a couple weeks ago and the water temp spiked to almost 90 degrees (yikes). Now we have ich! Our water chemistry is perfect! The Ph was a bit high but controlled that by removing a piece of drift wood.
<Unusual... such material/s generally lower pH with their decomposition>
From a treatment perspective we have done the following- removed the carbon from the Whisper and canister filter, used ½ of the full dose of Para Guard from Seachem as only two of the black mollies show spots and we don't want to kill the babies (I would rather extend the treatment cycle than risk losing them). We have kept the lights (compact florescent) off except for ~15 minutes to check for spots daily, closed the curtains to eliminate more light, done ~50% water changing using a gravel vac and have added the
recommended salt (done once so far). We are slowing raising the temp of the tank from 74 to 84- should reach 84 by tomorrow night.
<So far...>
I am happy to say that the two fish that visibly had spots are looking better, the babies and other fish do not look stressed although some are spending more time near the top � not sucking air though.
My questions:
- how long do we continue this treatment?
<I'd treat at full dose, per the bottle recommendations>
- How often do we really need to do a water change/vacuum if our chemistry is good (checking daily)?
<Not at all if so>
- Is there anything else we should be doing?
<Not likely>
- Some say that we should stop feeding the fish during this process? Rumor? I haven't read that on your site.
<I would continue to feed>
- Do we really need to keep the lights off (I miss watching the fish already)?
Thank you very much for your time and input.
Kerrie Minoia
<Welcome. Bob Fenner>

Beloved mollies dying en masse... please help! 6/3/09
Hello all,
About six to eight months ago I bought a 5 gallon rectangular tank and two pot-bellied mollies (Bonnie & Clyde), a small Penguin BIO-Wheel filter, and a Marineland submersible heater (as well as other supplies, such as a hydrometer, net, tropical fish food flakes, etc.).
<Ultimately this tank is too small to be successful with these fish, the need a larger tank to live out their lives, especially since these fish are highly interbred and not particularly resilient..>
After this purchase (I now know it should have been before )
I began to research my new fishy companions. I added one more female (Halo) to ease the effects of the male's 'drive', and bought Spirulina flakes for feeding. I fed them the Spirulina twice per day, with the tropical fish flakes every few days as a treat. I am not proud to say that I cycled the tank with the fish in it, as I already had fish and only one tank. The tank was kept between 76 - 78F. I attempted to keep my water slightly brackish, but experienced difficulties with keeping the water IN my tank... it didn't have a lid, and after 3 or 4 days, 2 inches of water would have evaporated away. Because of this loss, I never did water changes so much as water replacements.
<This does not accomplish the same thing.>
Much of the salt (Instant Ocean sea salt) ended up on the rim or down the side. Each time I added water, I also added one to two drops per gallon of Genesis (which purportedly removes chlorine from tap water), but did not increase the temperature of the water, which I know now I should (for the future, what is the best way to do this?).
<A small heater.>
My filter eventually seemed to stop filtering. The BIO-wheel turned irregularly, and eventually stopped turning at all.
<Best to clean the filter out, often salt will bind up the bio-wheel and needs to be removed.>
In a very short period of time, the water got pretty gross. NOW I know the wheel was fine, and it's the carbon filter pad that should be replaced, but I didn't then. Through all of this learning and unintentional error, my gorgeous mollies were VERY patient, and perhaps even semi-healthy. One Saturday morning I returned to my college apartment from home to see unexpected babies . After several attempts at counting them, I found that one of the females had given birth to 18 fry, one stillborn. There may have been more initially, but it took me a few days to obtain a breeding net ( http://www.thatpetplace.com/pet/group/10982/product.web) to round them up in, and none of them disappeared or were bothered by the adult mollies during that time. While I was in the FS searching for a replacement for my 'broken' filter, a breeding net and some fry food, I decided to upgrade and bought a brand new Eclipse HEX-5 aquarium kit.
<This is actually a downgrade here and still too small. A tall hex tank has less surface area, and as a result less gas exchange, and a lower bioload capacity than a regular rectangular tank.>
I rinsed the gravel and decorations from the old tank with hot tap water and moved them to the new tank. I filled the HEX with tap water treated with Genesis, and moved the fry over into their breeding net. The adult mollies were kept in a large Tupperware container with water from the tank during the maintenance and renovation, and then moved to the new tank. About three days after the tank switch, the female molly that I had originally purchased showed up at the top of the tank, dead and upside down. All the other fish, adults and babies alike, seemed fine.
<The cleaning of the gravel and decorations probably wiped out a good portion of your biofilter, causing the tank to recycle.>
It's been about two months since the tank switch and Bonnie's death, and in the past three days I've lost over 50% of my fish. First, a few of the fry died. I figured
<Are very sensitive to water quality issues.>
that I might have been overfeeding them, as all of the tank mates seemed fine (were eating normally, swimming around normally, etc).
<Check your ammonia levels.>
Yesterday the adults didn't seem hungry when I fed them.
<Not a good sign or mollies.>
Today when I came home from work, there were only 5 fry left and Halo (my treasured favorite) was dead on the bottom of the tank with what looked like tufts of white (possibly Columnaris?)...
<More likely just postmortem decay.>
Clyde swims in one place and shakes. What caused such rapid devastation in my tank!?
<Water quality issues here would be the leading candidate.>
I read that high water temperatures accelerate the progression of Columnaris, so I hesitate to heat up the water.
<I would not think disease is your problem here, instead start doing some water changes, a gallon a day or so at least until the tank settles.>
All I have done so far is put in a new filter pad.
<This actually is probably causing more problems at this point, removing whatever beneficial bacteria you have cultured. Water changes will help minimize this problem.>
At this point, I plan on increasing the salinity of the water and hoping to save those that I have left. I have been working tons of overtime at work and experiencing various other difficulties and I just don't feel like I've been giving my little guys enough time. I'm shocked and a little heartbroken - I don't want to be a bad fish 'mom'! I'm almost ready to give up on keeping fish altogether... please help.
<Your short term issue here is most likely your water quality. The new tank is still cycling and frequent water changes are necessary to minimize the impact to your fish. Long term you will need a larger tank to keep these fish healthy for their entire life span. In reality a 5 gallon tank is not appropriate for most fish, its just too small and unstable.>
Re: Beloved mollies dying en masse... please help! 6/3/09

The cottony material that formed on the dead fish has formed on my last Molly, and he is still living.
What would explain this besides post-mortem decay?
<Could be a fungal or bacterial infection, a broad spectrum antibiotic may help here, along with improved water quality and a small amount of marine salt.>
The water was cloudy and "fuzzy" looking before I changed
the filter pad, and has now cleared up considerably.
<Most likely a bacterial bloom due to the cycle, not uncommon. The filter pad gave more space for the bacteria to colonize, leading to a decline of the waterborne material.>
For clarification, I was under the impression that the
BIO-wheel was where the main culture formed, and that the blue carbon filter pads need to be replaced once a month
according to the gentleman at TFS). Is this true?
<The bio-wheel does hold a lot of bacteria, but so do all surfaces, including the gravel and filter pad. When these were cleaned and removed vast amounts of your biofilter went with it. The filter pad should be changed often but not at the same time as the gravel is washed, its too much for the tank to handle. The bio-wheels main benefit is not necessarily the amount of bacteria it holds, but the fact that it is highly oxygenated which helps the bacteria rapidly break down the ammonia and nitrite.>
Thank you,

Molly health question  05/23/09
We have a female bubble molly that has developed a string like discharge from her rear end that grew to about 5 inches long over a period of approx 3 days. Mid brown in colour & about 1/16 inch in diameter. It finally broke away & fish seems unfussed about it. Any suggestions as to what it is & should we be doing anything about it.
Geoff & Trudy
<Likely just a dietary thing; Mollies are herbivores and need a fibre-rich diet. Don't give them carnivorous fish food (standard tropical flake for example) but instead use things based on algae such as Spirulina (often sold as Herbivore Flake or similar). Also cooked spinach, lettuce, peas, etc.
Mollies are generally hardy, but they do have very specific needs with regard to water quality, water chemistry, and diet that you ignore at your peril.
Cheers, Neale.>

Possibly swim bladder? (Sick Mollies in a small freshwater aquarium at pH 7... par for the course really)   5/2/09
I am in need of some serious fish help! I have a 15 gallon tank [just a few months old, we started with a 10 gallon then with all the babies my fish had, it was time to upgrade] with 6 balloon belly baby mollies and 1 Pleco.
<Reina, the problem is that 15 gallons isn't enough space for either Mollies or Plecs,
and as sure as God made little green apples, some of your problems will come down to this fundamental issue. Mollies are best kept in tanks around 30 gallons or bigger. This is because they are extremely sensitive to poor water quality. Plecs need even bigger tanks; a 55-gallon system is the bare minimum. Plecs are simply huge fish, around 45 cm/18 inches after two years, and without masses of space and strong filtration, they cause major problems.>
I noticed right before I bought my Pleco that one of the babies, a beautiful orange spotted one, has been itching against the side of our little house. (medium size cottage with a spinning wheel) For fear of having parasites, I gave the tank parasite clear medicine as well as a did some water changes and a few days later [with no improvement] immediately took her out and put her in a 5 gallon medical tank by herself. [with introducing the Pleco to the tank, I made sure to do a water change so the Pleco wouldn't be harmed in any way]I monitored her behaviour there.
<Why did you stick the Plec in a 5-gallon tank? That makes no sense at all.
Always understand, a "hospital tank" should only be used if the conditions in that tank are at least as good as those in the display tank. A 5-gallon tank is too small for a Molly, let alone a Plec, and if the filter wasn't matured properly beforehand, then conditions are likely to be much worse in this tank than the main tank.>
A week or so passed by and I haven't seen her scratching against any items.
Unfortunately I have noticed that she has been swimming funny. I can't for the life of me figure out why.
<I can. When Mollies get sick, it's almost always because people keep them in the wrong conditions. They need warm (around 25-28 C) water with a high level of hardness, 15-25 degrees dH being about right. The pH level should be 7.5-8, and this is best achieved by raising the carbonate hardness.
Without exception, Mollies are healthier and easier to keep in water that is slightly brackish; add marine salt mix (not "tonic salt" or "aquarium salt") at a dose of about 6-9 grammes per litre of water.>
the water levels are all safe, maybe the high PH levels that mollies tend to enjoy is a little lower than standard but not of which I'd think would be of concern. [the level is reading 7.0] she seem to lay at the bottom a lot.
<This is far too acidic; raise the carbonate hardness and the pH should go up to the optimal level. The use of marine salt mix is the easiest way to raise salinity and carbonate hardness at the same time. Obviously, you shouldn't keep a Plec in brackish water, so that catfish will need a new home.>
yet swims up whenever I come near to watch her. I notice that she is pumping pretty hard to get herself to the surface[when she stops pumping she seems to sink a little easily]. Her tail is pointing down and her head is up- sort of as if her body was angled. would this be some form of swim bladder disease?
<No; this is the "Shimmies" and is very common when people keep Mollies in the wrong conditions. It's a bacterial infection of some sort, though the details are vague.>
I am getting increasingly worried. If it is, what should I do for her to help get her back to normal?
<See here:
Any advice is appreciated! Thanks, much!
- Reina
<Cheers, Neale.>
Re: possibly swim bladder? (Sick Mollies in a small freshwater aquarium at pH 7... par for the course really) -- 05/02/09

Thanks so much for your help. I guess I should have been a bit more descriptive, but it was pretty late last night, I guess my mind was falling asleep on me. The Pleco I have stays at a constant size. It is a Bristlenose Pleco. So I was told he would be fine in my tank.
<Ah, I see. This is why scientific (Latin) names are best! Ancistrus spp., the common Bristlenose catfishes, are good choices for tanks 15 gallons upwards. On the other hand, they will not tolerate salt, so aren't a sensible choice for the Molly aquarium.>
I put the molly that was scratching herself in the hospital tank. Not the Bristlenose. The Hospital tank is a tank that actually housed the baby mollies when they were first born. It's been cleaned, cycled, and kept up since babies were introduced to the big tank. I'm sort of confused because my mother has a 10 gallon tank, and 5 neon tetras and 3 mollies.
<Neons also need soft water, so they're another bad choice for life with Mollies. It's really important to review the needs of each species prior to purchase; at best, advice from "the guy" at the pet shop tends to be unreliable.>
2 of the mollies were some of the babies that came from my mother molly who passed away soon after birth. In her tank, they grew to adult size.
Mine haven't been growing as much, and I even invested in a bigger tank.
With mine smaller, and in a bigger space, I'm confused why with her crowded ten gallon tank which she doesn't maintain as often as I do, that the babies grew to adult size. Weird, Right?
<Not really; it's actually quite common for livebearers to [a] produce lots of babies despite [b] being kept in the wrong conditions.>
Yet, I have noticed there have been some growth in some of the babies. Is this slow rate of growth because my levels need to be higher?
<Could easily be the case that your baby Mollies are growing slowly because water chemistry and/or water quality isn't adequate.>
Anyways. I'm going to invest in this marine salt, I read somewhere about using salt to help the tank but I've only known about the aquarium salt. [I guess it is safe to say that after almost a year, I'm still new at all of
this.] After raising the levels, is there something that might help with the shimmies? or would making the tank easier levels to live at going to improve her condition?
<Tends to get better by itself, when conditions improve. Adding Maracyn or some other antibiotic can be used if it doesn't.>
Once again, thanks for all the help. Your site has been extremely helpful, keep up the good work! I'm glad there is somewhere fish lovers can go besides the sometimes not-so-knowing pet stores.
- Reina
<Do please keep reading! Plenty to learn, even with supposedly "easy" fish like Mollies. Good luck, Neale.>

Molly's  04/25/09
I hope you can help. I have a molly that I believe is sick. I can't find anything like it on the web. just behind it's gills are red spots almost like a chunk has been taken out showing the red flesh. both sides are like this. would you happen to know what this might be. she's about 2cm long, she is still very active and eating well. she is silver in colour. I have 2 others that show no signs of this thanks
<It sounds as if your fish is either developing an ulcer, or else has sustained some physical damage, e.g., from an attack by another fish.  Ulcers occur for a variety of reasons but are typically related to water quality problems. As you hopefully know, Mollies require very clean water (0 ammonia, 0 nitrate, less than 20 mg/l nitrate) but they are also sensitive to soft water conditions, requiring very hard, basic water to do well (pH 7.5-8.5, hardness 15+ degrees dH). They are best kept in brackish water, which is NOT the same thing as water with a teaspoon of salt added per gallon! As for physical damage, that depends on tankmates primarily, but also consider the ornaments in the tank, swimming space, clumsy netting by the aquarist or retailer, etc. Without a photo and some aquarium statistics (size, water chemistry, water quality) I can't really say much more than this beyond recommending a suitable, tested antibacterial medication, e.g., Maracyn or Maracyn 2, as opposed to fake cures like salt or tea-tree oil. Finally, please, if you write back, play nicely and hit the Shift key once in a while. We do specifically ask for properly capitalised sentences, not least of all because it makes a message easier to read. Proper English is the "currency" that makes this web site work, financially and otherwise. Cheers, Neale.>
Re: molly's   4/26/09

Thank you very much for the advice. I will check all of your recommendations. My first thought was an injury of some sort. Again I thank you
<Good luck with the fish, and hope it gets better! Cheers, Neale.>

Molly trouble   4/19/09
Hello to the crew at WWM!
I have looked throughout your website at possible causes that could be contributing to the illness that one of my mollies, Bass, seems to have contracted. My fiance and I jumped into the aquaria hobby about 18 months ago and haven't looked back! Since mollies were the fish we had the best luck with, we kept them. As they grew up and bred (and bred and bred and bred), we just kept increasing their tank size. The majority of our mollies now live in a 125 gallon, 6' long tank. Temp is 80 degrees Fahrenheit; ammonia is 0; nitrite is 0; nitrate is 40 (water change is tomorrow). They get dechlorinator and a bit of non-iodized salt, but that's it.
<Would up the salt, and rather than using cooking salt, switch to marine salt mix. Besides raising the salinity, marine salt mix dramatically improves the pH and hardness levels. I'd recommend 6-9 grammes per litre, the lower end if you have plants in the tank. Check your other fish are salt-tolerant before raising the salinity. Almost all general problems with Mollies just don't happen when they're kept in brackish -- rather than freshwater -- conditions. Your nitrate level for example is too high for Mollies, but the use of brackish water will far reduces the toxicity effect.>
About six months ago, we purchased a female molly from our LFS and we decided to name her Bass (we name most of our fish for identification purposes). Last weekend, around April 11, we noticed that she was
whirling. We immediately prepped our 10 gallon quarantine tank and used tank water from the 125 gallon tank and placed her into there with some Formalin and Epsom salts to treat what was suspected to be a swim bladder issue. We also stopped feeding her for three days, then started feeding her shelled peas only at one pea every other day because it takes a while for her to eat a whole one. She started swimming fine on Thursday, April 16, so we put her back home into the 125 gallon tank. Bass then started whirling again, so we put her back into quarantine. Of course, now she is swimming fine, and we are still feeding her peas and regular fish food on a pattern basis. I joke that I think she is faking. Other than whirling and swimming as if she is drunk, she acts just fine.
<Rocking, listlessness, and "treading water" in Mollies is commonly put down to something called the Shimmies, a catch-all name for something caused by a potential variety of things including poor water quality and certain bacterial infections (particularly Columnaris). Columnaris, also called Mouth Fungus, is bacterial infection common among Mollies and often revealed by white-grey patches on the face and body.>
Are there any suggestions as to what could be the cause of this behavior/illness?
Thank you very much!
<Would amend water chemistry as noted, and if you suspect Columnaris, treat accordingly. Cheers, Neale.>
Re: Molly trouble 4/19/09

Thank you for your quick and thorough reply!
<Happy to help.>
After I received the message in my inbox, I feel I may have needed to include a few more details than I did previously. The 125 gallon is home to only mollies of various ages, backgrounds, and types. It is sparsely planted at the moment because the light necessary for some better plants is expensive. We have already set aside funds for it and will be purchasing the new light at the end of the month, however. The plants will definitely help with the nitrate issue.
<OK. Well, since you're keeping Mollies, raising the salinity to SG 1.003 is a no-brainer. Any plants tolerant of salt will accept this salinity, provided they're otherwise happy. I have a list of salt-tolerant plants on my Brackish FAQ, here:
We used to use Instant Ocean (16 teaspoons for the tank in addition to 16 teaspoons of non-iodized salt) in the molly tank when we did water changes.
The problem was that the Instant Ocean stressed them out somewhat.
<Can't think why. If it's safe for seahorses and corals, better believe it's safe for Mollies!>
Our next step is going to be to find a way to get it set up on a drip system using an empty water jug, aquarium tubing, and a flow regulator (this is coming soon) so that we don't have to just dump the Instant Ocean mixture into the tank all at once.
<Mollies can be acclimated between freshwater and seawater within an hour.
Have done this many, many times. Certainly true for Sailfin and Black Mollies, might not be the case for the more inbred mutant forms like Balloon Mollies, but I don't keep them. Wild Mollies at least will tolerate
any salinity you throw at them. But, and it's a bit but, your filter bacteria may need to adjust to dramatic changes in salinity. From 1.000 to 1.003 shouldn't cause problems, but bigger changes might. Do always use a hydrometer to check the specific gravity; don't rely on teaspoons or such!
A basic floating glass hydrometer costs $5.>
When we were using Instant Ocean, however, we lost several mollies within a few weeks of each other.
<Just don't believe these things are connected, unless the Instant Ocean was somehow contaminated.>
They were in the category I call the "teens" -- older than fry, not quite adult.
<Not an issue. Mollies will breed -- readily -- in seawater.>
The symptoms they began to exhibit right after the addition of the Instant Ocean product were crooked spine and whirling.
<Doesn't sound like a salinity issue; sounds more like a sudden change in pH, exposure to toxins, or something like that.>
Those fish were immediately euthanized after the crooked spine was noticed (I will not prolong the suffering of any animal, no matter how attached I am to him/her/it).
Now we have Bass, who is fine in quarantine but starts moving around listlessly and whirling once she is placed into general population. Does this still sound like a myxosporea/nitrate issue?
<Myxosporea is not common in tropical fish because the parasite has a complex life cycle that requires intermediate hosts. So unless these Mollies have been kept in a pond, I can't see how Myxosporea enter into the discussion. As for nitrate, this is an Achilles' heel for Mollies, but it's difficult to pin down the "toxic level" accurately. They do seem to be nitrate sensitive compared to other livebearers, so by analogy to other
nitrate sensitive fish, levels above 20 mg/l probably make them more prone to sickness. But beyond that, it's hard to say.>
If so, I will gladly find some copper sulfate at our LFS later today.
<Apropos to what? Copper sulphate isn't much used these days because it's pretty toxic, though concentrations of 0.15-0.3 mg/l can be used for up to 4 weeks to treat external parasites and flukes. Won't do much for fungus, Finrot, etc.>
Thank you very much again!
<Cheers, Neale.>

Shaking Molly has white patches on her side 03/29/09
Hello everyone.
I have done a lot of reading but am having trouble figuring out what is wrong with one of my Mollies.
<When Mollies are sick, the very first thing to do is check the aquarium: they need warm (25-28 C) water that is hard (15+ dH) and basic (pH 7.5-8) and preferably brackish (SG 1.002+). Water quality needs to be excellent; zero ammonia, zero nitrite, and minimal nitrate. In freshwater aquaria, nitrate is a critical factor, though less so when kept in brackish or marine conditions.>
Last night she started to shake, but otherwise looked fine. She wasn't really hiding, but she was staying somewhat isolated from the other fish, all Mollies.
<"Shimmies". This is neurological and apparently related to the environment, and not caused by a pathogen, so far is known. So you should review conditions in the aquarium.>
Today, she has a white patch on each side. It doesn't look like there are spots or pustules; it looks more like an absence of color. Today she is hiding. She can swim if she has to, and it seems like she can swim in whichever direction she chooses, but she spends a good amount of time resting on the gravel. Her breathing looks ok, although maybe a little faster--I am not sure.
<Still sounds like the Shimmies.>
Several hours before she got sick, I noticed that two other females were shaking a bit. I thought they might be having babies, because another fish just had babies a few days ago. I added some salt (in water) to the aquarium, and I don't know if that helped, but the shaking stopped completely within a few hours, and all fish seemed fine. When the fish that
is currently sick started to shake, I thought she would recover as the other ones did, but she has not. Now she has these white patches on her sides.
<When you say "added some salt" what are we talking about here? Some people mistakenly assume aquarium salt (sometimes called tonic salt) helps. It really doesn't. Such salt is simply cooking salt, sodium chloride, and while it helps detoxify nitrate, it has no affect at all on stabilising pH and raising carbonate hardness.>
The water quality is good: no measurable amounts of ammonia, nitrates or nitrites. It is a brackish system with extremely hard water, approximately an 8.6 pH, and a temperature of 78-80 degrees F, depending on the time of day.
<Brackish water is created by using marine salt mix, such as Instant Ocean or Reef Crystals. In the case of Mollies, I'd recommend around 6 grammes per litre (roughly 0.8 oz per US gallon).>
Nothing in the environment has changed in the past few days, e.g., lighting, feeding schedule, etc. I change about 15% of the water once a week, the last change being the day before any of the fish started to shake.
What do you think is wrong with her? Is there anything I can do to help her and to prevent other fish from getting sick?
<It's certainly the Shimmies, and there's really no fix other than repairing whatever is wrong with the environment. Do see here:
Thanks so much for your help. I use your site all the time.
<Cheers, Neale.>
Re: Shaking Molly has white patches on her side 03/29/09

Thank you for your reply.
<Happy to help.>
I am sorry to say that she died yesterday morning, but I still would like to figure out what could be wrong with the environment for the sake of all of her friends.
As I said in my previous email, tests are showing no ammonia, no nitrite, and no nitrate in the water. I have been testing the water daily just to be sure, and it is consistently good. The aquarium is, in fact, brackish; SG 1.014 (marine salt, not aquarium salt). The tank is well oxygenated, the water is extremely hard and slightly alkaline--it comes out of the tap that
way, so these conditions are stable.
<All sounds ideal.>
Until I first I noticed the problem, the temperature was regularly 80 deg. F, although occasionally it would drop to 79 or sometimes 78 in the evening on very cold nights. I have since raised the temperature to 82F, and it hasn't dropped below 82 at night. (There is nothing I can do to control this temperature drop; I have two heaters running, one of which monitors the temperature and is supposed to adjust itself accordingly. It simply is cold here.)
<Such temperature changes are well within what Mollies can tolerate, so can't see this being the problem.>
I am concerned for the other fish, because I have seen a few others display shimmying behaviors in the past few days, although only intermittently. For example, they will shake for 10 minutes or so, then they will be fine for the rest of the day. Everyone is eating well and swimming normally, and there are many attempts at mating taking place. It's just that once a day
or so, a few of them will hide and shimmy--only the older ones. Haven't noticed any shimmying today, thankfully.
<All sounds like Shimmies. There's really nothing much to say in terms of healthcare; usually it's caused by environmental issues, though occasionally it's connected with Flexibacter columnaris infection, in which case an anti-Columnaris antibiotic or antibacterial could be used. Worth a shot, anyway.>
Any thoughts?
<Cheers, Neale.>
Update: No More Shimmies!  4/1/09

Thanks, Neale. I wanted to update you on an interesting turn of events.
When I received your e-mail suggesting use of an antibiotic/antibacterial, I decided to do a quick water change first. In doing so, to my surprise, I found that four of my fish had given birth. The next day, a fifth one.
Perhaps this was, in fact, what was causing all the odd behavior?
<Possibly, though I'm not aware of any connection (which doesn't mean there isn't one!). Mollies are generally pregnant 12 months of the year, so they're almost always going to give birth at some point through sickness.
So while there may be a connection -- perhaps a stressful labour? -- it isn't obvious that there should be one.>
Just in case, I am still treating the entire tank for columnaris. Since the second day of treatment (also the last birthday), I have not seen any shimmying. Babies everywhere, but no shimmies.
<Well, the end result is healthy fish, and even better if you have ten times as many as before!>
Thank you again!
<Happy to help. Enjoy rearing the baby fish; it's a treat! Cheers, Neale.>

Mollies: Sudden Death, Health, Overstocking, 3/28/2009
We have a 10 gallon tank containing three Glofish and one Cory cat.
<Very close to overstocked for a 10 gallon aquarium>
Ammonia 0ppm with Nitrite <0.3 mg/l and pH 7.0
<Nitrite too high, you want this to be zero., and the pH is too low for Mollies.>

We purchased a black molly today and she died almost instantly when added to the tank.
<Can be a combination of things. Water conditions inappropriate for Mollies, nitrite levels, and perhaps the Mollie was in poor health to begin with.>
Is it possible that she was sick, in shock or was it something with our tank.
<There is definitely something wrong with the tank if your nitrite levels are above 0>
I don't want to try another Black Molly if we have a problem.
<Mollies are not appropriate for this system, Mollies need hard, almost brackish water to do well.>
If she was sick, is it possible that my tank is now infected and if so, how do I test?
<Maintain good water quality, keep up with regular changes.>

Mollies with Columnaris and Ich -- 03/22/09
Hello Crew,
<Hello Carla,>
I'm in a bit of a quandary. I purchased three mollies the day before yesterday, and placed them in my cycled 10 gallon quarantine tank (pH: 8.1, ammonia: 0, nitrites: 0, nitrates: 0 -- I had a bunch of extra cuttings so the tank is stuffed with live plants).
<Mollies don't do well in small tanks. They're very sensitive to nitrate as well as ammonia/nitrite, and in small tanks it is very difficult to keep them healthy for long. Minimum tank size for small Mollies (Shortfin mollies, black mollies, balloon mollies) is 20+ gallons, while large Mollies (Sailfin mollies, liberty mollies) is over 30 gallons.>
Unfortunately yesterday I observed that one of the mollies had what we used to call cotton mouth or mouth fungus.
<Very common with Mollies, especially when kept in freshwater conditions.>
I understand, from researching your site, that this is likely Columnaris (bacterial).
<Indeed. You will need a suitable antibiotic or antibacterial (as opposed to a make-believe solution such as tea-tree oil or salt.>
Today I also observed two Ich spots (sure glad I quarantined). I was going to go the salt + heat route, but I learned (also from researching your site), that Columnaris grows faster with higher heat.
<Your options are limited here, but in this case, I'd raise the salinity to deal with the Ick, and treat with an antibiotic/antibacterial at the same time. Since Mollies are best kept at SG 1.003, I'd recommend 6 grammes of marine salt mix per litre of water. There's not much point trying to keep Mollies in a freshwater aquarium because they rarely (seemingly, less than 50% of the time) do well. You're also fighting with one hand behind your back because the tank is so small, so a difficult job is being made twice as hard.>
My questions are: Should I raise the heat, and how I can treat both the Columnaris and Ich concurrently? Also, should I remove my plants?
<Plants will not be affected by antibiotics or antibacterials used correctly, and a salinity of SG 1.003 is fine for hardy, salt-tolerant plants.>
Thanks very much for your help and your wonderful website.
<Cheers, Neale.>
Re: Mollies with Columnaris and Ich   3/23/09

Thanks very much for your help. The Mollies are currently in a ten gallon tank because they are in quarantine (their permanent home will be a 40-gallon heavily-planted breeder tank).
<Ah, that makes sense. A 40-gallon system will be perfect.>
The water parameters of that tank are:
Ammonia: 0
Nitrite: 0
Nitrate: 0
pH: 8.2
Carbonate hardness: approximately 200 mg/L CaCO3
<That's 200/17.8 = 11.2 degrees KH. That's extremely high, and while perfect for Mbuna or Central American livebearers, a lot of other fish will find that a bit on the hard side for their tastes. Do be aware when choosing fish and plants.>
Their tankmates will be Wrestling Halfbeaks, Scarlet Badis, White Clouds, and Threadfin Rainbows.
<Halfbeaks will thrive, the others should tolerate, but may not show optimal colours or longevity.>
I was hoping the Mollies would do well without salt because of the high pH and hardness, and I wasn't sure (aside from the Halfbeaks) whether the plants and other residents would appreciate the salt.
<Plants that tolerate hard water generally do well in slightly brackish water too; species such as Vallisneria, Hygrophila, Java ferns, hardy Crypts, etc. If you have plants that need soft water, chances are they
aren't going to thrive a this level of carbonate hardness either, so it's a moot point. As for the fish: Halfbeaks tolerate salt well, but the others are truly freshwater fish.>
But I will add salt and remove some of the other residents and non-salt tolerant plants if necessary.
<Would be my recommendation. Mollies deserve a tank of their own: they're spectacular fish, and wonderful pets. But they are finicky in freshwater systems. They need perfect water quality. You might decide to medicate them in the quarantine tank, and when they're healthy again, try them out in a plain freshwater tank. With luck, you'll be okay. But if you find you're constantly having to deal with Fungus and Finrot, remove the Minnows, Rainbows and Badis, add a little salt, and maintain the system at SG 1.002-1.003.>
I've started to slowly raise the salinity of the quarantine tank, and I'm off to the LFS to pick up the antibiotic and a hydrometer. I believe we have Maracyn and Maracyn II available here (Canada), so I will purchase
A couple more questions, if you'll bear with me:
<Of course.>
Which Maracyn product would be most effective against Columnaris?
<Maracyn rather than Maracyn 2 is usually used first. It contains Erythromycin, which should work on Flexibacter columnaris.>
If the Mollies recover, when would it be safe to place them into my main tank (so that Columnaris does not contaminate that tank).
<Columnaris, like Finrot, is a disease latent in all tanks, and the bacteria involved is presumably harmless most of the time. It appears not because a fish "caught" the disease, but because the fish was somehow
weakened, and its immune system overwhelmed. So provided the other fish are healthy, you shouldn't worry about cross-contamination.>
Thanks again...
<No probs.>
<Cheers, Neale.>
Re: Mollies with Columnaris and Ich - Update 04/03/09

Thanks very much, Neale, for your advice. Just thought I would give you an update on the Mollies. I used the salt + heat treatment for the Ick, and the Ick has disappeared.
For the mouth rot, I couldn't find Maracyn at my LFS, so I used TC capsules (tetracycline). The mouth rot hung around during the course of the treatment (5 days), and then I had an ammonia spike (the packaging on the TC capsules claims that they will not affect the biological filter, but I suspect otherwise).
<Oh dear.>
Unfortunately one of the Mollies died (oddly, it was the healthiest, dominant female).
<Sorry to hear that; I wonder why?>
I subsequently performed 75% water changes for the next several days to control the ammonia, used activated carbon to remove the tetracycline, then added some nice filthy filter media from my other tank to repopulate the nitrifying bacteria. Over the next several days, the mouth rot on the remaining Mollies disappeared, but I'm not sure if I can attribute it to the tetracycline or the water changes.
<It's a combination: the antibiotic kills off the bacteria, but improved water quality allows the fish's immune system to repair the damage and prevent re-infection>
Anyway, the remaining Mollies have recovered, and in a week or so, I will remove them from quarantine and place them in my 40-gallon tank.
Also, you were right, the salt did not seem to affect my plants (Hygrophila polysperma, Hygrophila corymbosa, Rotala rotundifolia, Java Moss, and Bacopa monnieri).
<Not sure about Rotala, but certainly the others are happy in brackish water, let alone slightly salty/warm water of the sort used to treat Ick.>
Thanks again for your help,
<Thanks for the update, Neale.>

Sad State of a Dalmatian Molly
FW System/Stocking/Toxic Water Conditions 3/18/2009

Dear WWM Crew-
<Hello Kim, Mike V here.>
I have tiresomely researched what could be wrong with my Molly- but to no avail. Please help! This is quite a detailed history, but hopefully my including it will allow your expertise to see what I cannot. The situation is as follows:
<Will certainly try to help.>
I wanted to expose my son to the wonderful world of fish and begin teaching him how to properly care for an aquarium. I have had an aquarium in the past and understand it is not a "passive" pet. I also understood that I would be doing all of the work (he's only 2) so I refreshed myself with books from the library, researched on line and asked advice of friends.
<Kudos to you for researching!>
In January, 2009 I decided upon a 10 gallon tank and chose 5 Platys and 2 Dalmatian Mollies.
<A bit overstocked for a 10 gallon tank. Mollies are not easily kept in these conditions.>
I was using a Bio-Wheel 100 filter. I am religious with 20%-25% water changes every Saturday, and am careful to maintain a water temperature of 76-78 degrees. I add aquarium salt once per month for the Mollies and use stress-zyme and water conditioner with every change. My fish were doing well and I had 2 batches of fry- some were Platys and some Mollies. I installed a floating breeder trap for the babies, and purchased baby brine shrimp for the fry, feeding them ½ frozen cube per day. I feed the elder-fish flake food, then substitute a treat of frozen blood worms or Daphnia once a week.
<Sounds good so far.>
Last month my filter died. Stopped completely- I do not know why. I purchased another filter immediately and installed it the next morning. I was encouraged to buy an Aqueon. The Bio-Wheel 100s were out of stock, and I was told this was a better filter anyway. Approximately 3 days after the filter change, all but 3 of the babies have died, along with one of the Dalmatian Mollies. I tested the water and came back with a horror- Ammonia at nearly 5 ppm, Nitrite and Nitrate off the chart and a Ph of 7.5.
<Mollies are much more sensitive to water quality than the Platys>
Obviously, the water conditions were atrocious. I did an immediate 50% water change, followed by a 25% water change every 3 days for a week, hoping to clear out the mess.
<The biological filtration was removed when the old filter stopped running, forcing the tank to cycle over again..>
Current conditions are Ammonia at 0.25, nitrate/trite at 5 and Ph at 7.8. I think the water changes have really stressed my molly- she hovers by the heater, head up, near the top of the tank (not floating).
<Not the water changes, the toxic water conditions.>
My Platys and 3 remaining babies are doing well. However, I cannot get the Ammonia or Nitrate/Nitrite to 0. I do not know what is happening. Is it possible the helpful bacteria Bio-Wheel in the
older filter disappeared when I switched filters?
<This is exactly what happened. The biological filtration will come back with time.>
The day after the male Dalmatian molly died, the remaining female Dalmatian Molly swam around
incessantly. I would say frantically. Now she hovers close to the heater (temp is 78) and faces head up toward the top of the water. She is swimming (not floating), and comes out for food.
<Ammonia\Nitrite poisoning>
I will continue with water changes until 0 is reached for ammonia and nitrate/nitrite, but is the frequency of
water changes also destroying any good bacteria growth or causing her additional stress? Please advise- I am hoping to save my Molly.
<Monitor water quality closely and stop feeding. by feeding, you are adding more ammonia to the tank. Add a product called PRIME - It will detoxify the ammonia, nitrite and nitrate.>
Thank you-
<My Pleasure>
Re: System/Stocking/Toxic Water Conditions Follow Up 3/19/2009
Re: Sad State of a Dalmatian Molly

<Hi Kim>
Thank you so much for you quick and helpful reply!
<You're very welcome>
Although I was unable to find PRIME at my local store I did purchase and use AmQuel Plus.
<That will work as well.>
I am VERY happy to say that my tank is already testing better.
.<Excellent news.>
I did an additional 20% water change today, added the AmQuel Plus and several hours later re-tested the water. Although Ammonia is still registering at 0.25, the Nitrite is at 0.5 ,Nitrate at O and Ph at 7.4. The water changes may have helped this before the AmQuel (unless it gets such quick results)- but I am still thrilled.
<A combination of both really, the AmQuel detoxified the ammonia and nitrite - which is why you are still detecting it.>
My fish are breathing a sigh of relief as well - especially the Molly.
She is swimming around, no longer hovering and seems quite alert. I have 3 additional questions:
1. You suggested I stop feeding for the time being. For how long? Until ammonia is at 0, perhaps?
<Stop feeding (or feed very little every two days) until the ammonia and nitrites drop to zero.>
2. Do you suggest I add the Amquel Plus with each water change until ammonia is at 0? (The directions on the AmQuel are unclear!)
3. What could I have done to avoid this? When a filter fails like that is there a proper way to protect your fish - I don't ever want to put them (or me) through this again.
<The biological filter was on the bio-wheel. When that was removed, the tank crashed. In my opinion, this is the one significant weakness of a bio-wheel system - they work a little too well. Do make sure that your
biological filter does not get disturbed. You can rinse them off in dechlorinated water, but that is all. If it were me, I would add a few small pieces of dead reef rock (A couple pieces of rubble) - it will buffer
your system slightly, and is porous enough that a bacterial colony can be established inside the tank as well as on the filter.>
Again, thank you. I am hopeful my tank will finish its new cycle soon and all will be well in the aquarium again. For now- my Molly and friends thank you.
<Again, my pleasure, do let me know how it all turns out.>

Itching, shimmying, clamped fins? Reading, FW   2/24/09 Hello, I have been reading up and I think some of my mollies either have ich or parasites. Some of them are glancing against objects such as gravel, plants, my log ornament etc... I have seen that many medications require to "remove carbon from filter." What does that to anything and how would I go about doing that? <Is to prevent the carbon from chemically filtering, removing the medication> If this helps I have a 12 gallon eclipse system that has a bio-wheel. I have 3 full grown mollies and one younger, smaller one, and two guppies. I have already removed one fish with serious "itch", shimming, and clamped fins (The symptoms in my main tank.) My nitrate and everything is fine but my nitrite increased to a scary level. I have been doing daily 30 percent water changes for around a week but nothing has helped. Plus what medication/advice would you say to use to help my tank? Thanks for everything, Hannah <... In order to help you we need to know what your water quality is, the history of this set-up... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  and the linked files above... and write back with information as others have. Bob Fenner>  

Black molly with shiny scales near gills   2/21/09 My son has a black molly in a ten gallon tank that appears that its gills are turning shiny (or falling off...can't tell). It was in serious distress a few days ago (not eating, staying at the bottom of the tank with little movement), but seems better as I discovered the pH was very low. I am currently adding salt (as Mollies need) and baking soda staggered between water changes to get the levels as needed. The molly is responding, but the shiny area remains near the gills and on the head a bit. Might this be velvet or Ich? What is the difference in a Molly? I am also noticing a few (3) small spots on its body. This molly is in a 10 gallon tank with 4 tetras, 1 goldfish, 1 Gourami, 1 Otocinclus, and 1 very young platy. Your help is appreciated...Wanda <Wanda, Mollies aren't really good community fish and certainly can't be kept in a 10 gallon tank. They're too sensitive to water quality issues and pH variation. The fact the pH has dropped in your tank clearly shows that it is dramatically overstocked. There's no real solution to this problem until you up the size of the aquarium to at least 20 gallons for Mollies and in all honesty 30+ gallons for Goldfish. Me telling you anything else would be lying. In the short term, adding marine salt mix (not tonic salt or baking soda!) at a dose of 6 grammes per litre will dramatically improve your success with Black Mollies. While Platies will tolerate such conditions well enough, Tetras, Gouramis, Goldfish and Otocinclus will not. So it's an either have those fish OR have healthy Mollies, but there's nothing really in between. It's most likely your Molly has either Finrot or Fungus, both being exceedingly common when Mollies are kept inappropriately. The face region gets silvery as excess mucous is produced by the skin. Treated properly (e.g., with anti-Finrot medication other than Melafix/Pimafix) it clears up quite well. But it will come right back if the fish is kept in the wrong conditions. http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Finally, please let me stress than small children don't "have" pet fish, or really any other kind of animal. The responsibility lies with their parents, and it's up to you to decide whether to own pet animals and if so, to make sure those animals are correctly maintained. In this instance, there's a too-small tank filled with fish that are fundamentally incompatible with one another. Little kids don't know better, but their parents should be able to navigate a book store or library prior to purchase. The fact Mollies are difficult fish is far from a secret, as is the fact that tetras and Otocinclus are social animals that need to be kept in groups of 6+ specimens. I've written a few words on stocking 10-gallon tanks at the link below, and would suggest you peruse this for some ideas. If upgrading your tank isn't an option, any decent retailer will take back unwanted fish, usually for credit. http://www.wetwebmedia.com/ca/volume_5/volume_5_3/stocking.htm  Cheers, Neale.>

Poecilia/Mollienesia (health, water quality)  2/10/09 Hi, my name is mike. <Hello Mike,> I have a white balloon Molly that is sick. My water parameters are: pH is 7.2, Ammonia is 0 ppm, Nitrate is 5.0 ppm, Nitrite is 0.25 ppm. The tank is a 20 gal. freshwater with no salt at all. <Well, there's the first problem. The tank is too small and has the wrong water for Mollies. Mollies need big tanks because they are sensitive to poor water quality. You have poor water; ergo, your Mollies will get sick. In fact the nitrite level is way too high for any aquarium, and you need to URGENTLY review feeding, stocking, and filtration. Your tank will never work correctly with 0.25 mg/l nitrite: fish will constantly be getting sick. As you mention salt, you probably realise Mollies appreciate salty water. It isn't essential in a well-run, big, clean tank with hard, alkaline water -- but your aquarium is none of those things. The addition of marine salt mix (not tonic/aquarium salt!) will raise the pH, hardness, and salinity to levels that favour Mollies, and indeed many other livebearers as well.> The tank is shared with two Goldfish, One Dwarf Gourami, One Angel fish, two Platy's and two Cory's. <Platies are good companions for Mollies, Goldfish potentially so, but the others shouldn't be here because they don't really like brackish water. Up to around 3 g/l, both Platies and Goldfish will do fine.> None of the fish nip at each other and all look well after almost three months together (after cycling for a month) The Molly, just one day ago, has been laying on the bottom of the tank breathing very shallow, not eating and not passing waste, listing and swimming nose down on occasion and backwards sometimes, but every once and awhile will swim just fine and go to the surface (but very rare) the fish looks like it's paralyzed to a degree. <Shimmies or equivalent... dying...> The Molly has Been in a separate tank for about 20 hours now, filled with some water from the original tank and some new water, both tanks have identical water and the filters are the same with an air stone working off the same air pump as in the larger tank. I've looked through most of the site about Mollies and some about Angel fish, and found similar but not the same symptoms. I feel horrible for the poor thing and was wondering if there is anything at all I could do to help it. Thank you in advance for the help trying to make the fish better. <Angels and Mollies are not compatible. Review the needs of Mollies, set up a tank as required, and enjoy better success. http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  Cheers, Neale.>
Re: Poecilia/Mollienesia (health, water quality)   2/11/09
Thank you so much for your reply and the advice you gave, but unfortunately the molly didn't make it. I feel horrible that my incompetence killed an amazing little fish like that. <Not incompetence, merely lack of knowledge. Do read a fish encyclopaedia before spending any money: it's pretty widely known Mollies like a little marine salt mix in their water, and while not essential, it does make them much easier to keep. Because of this requirement, I recommend keeping them with species that tolerate or enjoy a little salt too, such as Platies, Swordtails, or Guppies. Indeed, most any livebearer will do well. Australian Rainbowfish and many Killifish also fall into the salt-tolerant category, so it's really not that big of a deal. A box of Instant Ocean marine salt mix will last months at the required dosage, so it's a lot cheaper than [a] buying new fish and [b] buying fish medications.> I bought a larger tank yesterday afternoon (along with a canister filter and new sandy substrate) and look forward to creating a much better environment for the fish that have me and my family glued to the tank for hours at a time (well maybe just me most of the time) <Ah, a tank with a sandy substrate opens up LOTS of options, such as Gobies. Look up Knight Gobies (Stigmatogobius sadanundio) and Violet Gobies (Gobioides broussonnetii) as examples. http://www.wetwebmedia.com/brackishsubwebindex/knightgobyfaqs.htm  http://www.wetwebmedia.com/brackishsubwebindex/bracgobioids.htm  They need brackish water, and positively THRIVE alongside Mollies at, say, SG 1.005 (about 9 grammes salt mix per litre). Violet Gobies are big, ugly but really funky animals that make great pets. Faces only a mother could love! Watching them filter feeding on live brine shrimp is one of the most fun things in the hobby. They're gentle giants, and won't even eat livebearer fry if properly fed on worms, crustaceans and the odd algae wafer.> I do thank you for the advice and all the priceless information you guys diligently dole out about such a great hobby and hope that one day I will be able to help someone with as well. <We're happy to help.> Thanks so much Mike <Cheers, Neale.>

Molly disease? 1/19/09 Hello, <Hi> I bought a female Sailfin molly from a pet store 2 days ago. It was in a brackish/ marine tank (1.019ppm), and when I got home, I realized it had around 6 white spots on its tail that didn't look quite like ich, or fungus. Ich treatments didn't work, so she is on Pimafix now. What should I do? Thanks <What water conditions is it in now? If it came home with "Marine Ich", Cryptocaryon irritans, and it is now being kept near FW levels then that alone will solve the problem. Also there is no treatment that would cause you to see a change in just two days, all need the parasite to cycle to a different stage of it's lifecycle to be effective. I would discontinue the Pimafix, as it is worthless at best, and monitor for now. Also in future correspondence please spell and grammar check your queries before submitting, otherwise we need to do this for you before posting.> <Chris>

Sick Dalmatian molly, 1/19/09 Hi I have a 20 gallon tank. <Ok> I started it about three weeks ago with a male Dalmatian molly. And about four days later I added 2 female Dalmatian mollies, then I got three peppered Cory cats about a week after that. <I am guessing this is a freshwater tank, in which mollies are very difficult to keep. You would probably be better served switching them out with one of the other livebearers, such as swordtails or Platies which are much more forgiving.> Then I was having my water tested about 2-3 times weekly and everything has been fine so today we decided to get some more fish to finish our tank. We got 3 golden mollies, 4 guppies (2 female, 2 male), 7 neon tetras. <This is too much and incompatible life. Mollies and guppies do much better in brackish water, or at least very hard freshwater, while the tetras are at the other end of the spectrum needing soft, acidic water. Also neon tetras can be very difficult to keep as well, definitely not what I would consider "beginner" fish.> I asked the guy at the Petco if that would be to many fish for my tank and he told me no as long as I do a water change every three weeks. <I disagree, I think you do have too much, and fish that just don't share the same environmental needs.> But I got home and let my fish get use to the water for 20 minutes before adding then I put them all in. And now my male Dalmatian molly will sit at the bottom of the tank and he kind of jerks from side to side I'm not sure if he's just stressed out from me adding all of the fish at once or if something else is wrong with him. <Could be water quality related, adding this much life quickly can cause ammonia spikes as the bio-filter bacteria catches up to the new waste levels. The mollies would be the first fish to show signs of this.> I really don't want to lose him is there anything I can do for him? Thanks, Cherie <For now lots of water changes and minimal feeding until parameters stabilize, but I think you will need to address your stocking choices to help you achieve long term success. Please see here for more on Mollies http://www.wetwebmedia.com/FWSubWebInd ex/mollies.htm   .> <Chris>

Molly Behavior/disease  1/4/09 Hello, I have a 55 gallon freshwater community tank. I have some tetras, livebearers, and small catfish. I specifically have 4 small black mollies (still babies), 4 silver mollies, and 1 starburst molly. My water is perfectly fine. My male silver molly has been acting strange. He hides in every corner he can find, and when not hiding, he is swimming behind plants, head up. He never eats the food, and just hides. He acts sick, but there is nothing on his skin. 3 of my 4 black mollies are in a quarantine tank for lip fungus. Help! <Hello Rachel. One problem with Mollies is that they are not reliable freshwater fish. Most aquarists experience what you do when they are kept in freshwater tanks: lethargy, loss of colour, odd swimming behaviour, and random diseases including Finrot and fungus. The only 100% reliable way to maintain Mollies is to treat them as brackish water fish. Buy some marine salt mix -- not "aquarium salt" or "tonic salt" -- and add the marine salt mix to each bucket of water at a dose of around 5-6 grammes per litre. Marine salt mix contains carbonate salts that raise the hardness and sodium chloride that raises salinity. Together these things stabilise the pH and reduce the toxicity of nitrate, and it appears to be these things that help. (Tonic/aquarium salt only contains sodium chloride, and so doesn't do both these things, and is consequently a waste of money.) Mollies thrive in brackish water, and at low salinities so will other livebearers including Guppies, Platies and Swordtails. But do understand that most catfish and tetras do not appreciate brackish conditions, and consequently shouldn't be kept with Mollies. It's a very common mistake for people to buy Mollies for community tanks -- despite the fact most aquarium books state clearly Mollies prefer slightly saline conditions. Do read here for more: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm Cheers, Neale.>   Thanks! <Most welcome. Neale.>

Molly Disease Question Hello Neale, Earlier I asked about my molly acting strange, and not swimming, and he died. I have 9+ mollies and all are completely healthy, so I really don't want to change my tank to brackish. I was worried if that was some kind of disease, and will it spread to my other mollies? <It isn't a disease so much as an environmental issue. In freshwater aquaria, Mollies simply aren't durable. Put it this way, something like 50% of the Mollies stuck in freshwater tanks die within a few months. Sometimes it's from an obvious disease like Fungus or Finrot, and sometimes from something probably related to poisoning of some type, resulting in lethargy and odd swimming behaviours, what aquarists call "the Shimmies" after the dance. Either way, the Mollies die. But when Mollies are kept in brackish or saltwater tanks (yes, saltwater tanks) they are astonishingly hardy, and can be used even to cycle filters! Your Mollies may well be fine in your freshwater aquarium, but three, six, twelve months down the line things could be (and likely will be) very different. It is absolutely true that Mollies are usually freshwater fish in the wild, so they don't "need" salty water in the wild. But under aquarium conditions, for whatever reason, adding a small amount of marine salt mix seems to make all the difference. I recommend around 5-6 grammes of marine salt mix (Instant Ocean, Reef Crystals or whatever) per litre of water. This won't cost much, and at this dose, you can keep Mollies perfectly well with other livebearers.> I don't want my very nice mollies to die. I did a complete water change yesterday, and all are fine so far. <OK.> I would like to know what was that disease? <It's honestly a mystery. At the moment, either nitrate/nitrite toxicity (which sodium chloride reduces) or pH variation (which carbonate hardness prevents) are the suspected issues. Either way, marine salt mix counters the two problems, and thereby provides a useful tool. If your tank has a high level of carbonate hardness (7+ degrees KH) and zero nitrite and nitrate, you might be able to keep your Mollies just fine without marine salt mix. But the reality is that for casual fishkeepers who don't have the time to fuss over water chemistry and quality, and just want to keep their fish the easy way, in local tap water, changing 25% each week, adding marine salt mix is the solution.> Thanks! <Cheers, Neale.> re: Molly Disease Question Ok! Thanks for all your help! <No problems. Cheers, Neale.>

White Feces ~ 01/01/09 Hello, <Hello again!> About a year ago I emailed you about my sick mollies, since then I moved them into a brackish tank, and they have been perfect! <That's the idea!> I even added two more females and was surprised to find baby mollies a few days later. The babies are all grown now and everything has been great, until today. I noticed today that my adult balloon molly, Flo, had white stringy fecal matter hanging from her bum, that has not dropped, its been there for more than an hour. <There are really three things that can be relevant here. If there are red worms appearing from the anus (usually obvious because they move) then the Molly is infected with Camallanus and will need to be treated with an anti-worm medication. http://www.wetwebmedia.com/FWSubWebIndex/nematodesfwf.htm  If the faeces contain much mucous, so that they appear pale, often semi transparent, then your fish might have a Hexamita infection, and will be needed to be treated with an anti-Hexamita (Hole-in-the-Head) medication. Hexamita is commonly associated with lethargy and general lack of condition (pale colours, weak swimming, etc.). http://www.wetwebmedia.com/metranidazole.htm Finally, there's plain vanilla constipation: very common where herbivorous fish such as Mollies are concerned. In this case the faeces will be coloured, often brownish or off-white, but solid rather than semi transparent, and dry looking rather than mucous covered. Mollies need to eat mostly green foods, and in the aquarium things like thinly sliced cucumber and sushi Nori sheet work great alongside a balanced algae flake or algae wafer staple food. Daphnia and brine shrimp are good aids to constipation, as is adding small amounts of Epsom salt. Although the article linked here is written for Mollies, it applies 100% for Mollies. http://www.wetwebmedia.com/FWsubwebindex/gldfshmalnut.htm  > I have never seen this before, and after reading a bit online, I am very concerned that she has parasites. <By all means try a systemic anti parasite infection that treats worms and Protozoans, as they're the two likely causes of troubles in the digestive tract.> I am very attached to Flo, she is my first fish. What should I do? Should I wait to do anything? How do I treat her, and not kill the babies? <Medications safe for Flo should be fine with her babies.> The mollies are in a 16 gallon brackish system, currently there are 14 mollies in the tank, 5 of which are babies. I just did a 25% water change today, and all levels are normal. Please Help! Thanks, Lauren <Hope this helps, Neale.>

Sick Balloon Molly   11/25/08
Hi there, I wrote to you a little while ago and I think you probably saved my fishes, I'm just hoping you're able to do the same again!
I have a 90L tank with 2 female mollies, 5 guppies, and about 20 Molly fry.
About 2 weeks back I noticed that my Dalmatian balloon molly was acting a little subdued, hiding and not swimming about much. I checked the levels and the nitrites were high, I sorted those out and she seemed to go back to normal. I've recently noticed all of the fish (including the fry) scraping themselves on everything solid in the tank, but none had any outward signs of parasites. I went out and bought Sterazin Gill and Body Flukes treatment, and have been using the recommended dose. After 2 doses, I have come home to find my Dalmatian molly, pointing downwards, trapped between a plant and the wall. I thought she was dead but noticed she was still breathing. After bringing a net close to her, she swum off but has looked very ill since. Her stability seems severely affected, she's floating all over the place, just moving with the flow of the water, seemingly unable to control her movements, and bashing into things. She's often completely vertical, either pointing either up or down. Occasionally she'll come to rest in a plant upside down, and stay there motionless until I get scared and make her move. What's wrong with her? Do you think that I can save her? And should I stop the fluke treatment? Thanks for you help
<Sterazin is a medication that has been around for years. It is generally well regarded, and I'd be surprised if it was causing ill health, assuming it was used correctly. Do check you dosed the tank correctly: all medications are poisons, and the "art" is using them in the right amounts.
When measuring out the dose, it's important not to overdose. It's also a good idea to increase aeration when treating, because sometimes these medications cause the amount of oxygen in the water to drop. Also you have to remember to remove carbon from the filter; if you don't, the medication gets sucked up by the filter without doing its job. In any case, the thing with Mollies is that it is extremely difficult to separate actual diseases from the fact they almost never do well in plain freshwater conditions. I'd insist they be kept in brackish water conditions, at least SG 1.003 (about 6 grammes marine salt mix per litre). It's remarkable how many sick Mollies pep up when kept in brackish water conditions. The "treading water" behaviour often seen with Mollies is called the Shimmies, and is particularly common in tanks where Mollies are kept in freshwater. And no, adding a teaspoon of tonic salt per gallon doesn't make an aquarium brackish! Besides salinity, nitrate is highly toxic to Mollies, as are rapid pH changes, so these are two factors to review. Since Mollies and Guppies both do extremely well in brackish water, adding marine salt mix is the cheap and easy way to keep them in good health. Cheers, Neale.>

Re: black mollies   11/25/08
hi its me again so I went looking for marine salt and cant find it can I use the aquarium salt and I have also bought Ick remover I put some in do I do my water change every day for two weeks or every other day?
<Marine salt mix is better. MUCH better. If you're serious about keeping Mollies, make an effort to get (perhaps mail order) marine salt mix.
Ordinary aquarium salt is not nearly as good. It doesn't raise the pH and it doesn't increase carbonate hardness, both critical to ensuring Mollies stay healthy. Some people make the mistake of thinking aquarium salt is a cheap alternative to marine salt mix: it is not! Marine salt mix is better.
If you live in North America or Europe, buying marine salt mix should not be difficult. As for water changes, ordinarily you should be doing them weekly, or at least every two weeks if the tank isn't heavily stocked. But when using medications, usually the instructions of the medication will tell you when to do water changes. Commonly you do NO water changes until AFTER the last dose. Finally, please use proper grammar next time (e.g., capital letters). We often just bounce back messages that ignore this rule.
You've been warned! Good luck, Neale.>
Re: black mollies, sys.  11/25/08

Hi, is Marineland Instant Ocean Marine/Reef Sea Salt the kind of salt that I need? I'm going to order in online but I want to make sure it's right.
<Yes indeed! Absolutely perfect. Instant Ocean, Reef Crystals, Crystal Sea, Kent Sea Salt, Petco Premium Sea Salt... buy whichever is cheapest in your neighbourhood. All are perfect for brackish water fish and superb for use
with livebearers such as Mollies and Guppies. Use 6 grammes per litre of water (about 0.8 oz per US gallon). This isn't very much: between 15-20% the amount needed to make normal seawater, so a box that makes 25 gallons
will actually make around 150 gallons of water suitable for your Mollies.
Cheers, Neale.>

Re: Help! Mollies/BB Gobies 11/17/2008 Hello, again, <Hi there, BobF this time> I had written in a couple of months ago with a concern about my Dalmatian mollies after the BB gobies I had purchased all died (see below). <Noted> Since then, everything had been fine with the mollies, until the other night. My adult molly, Lucky, seems to be ill - but I'm not sure if she is really sick, or just getting old. I got Lucky 10 months ago, but I'm guessing she's much older since the babies she had when I first got her are still only half her size. Anyway, I noticed Lucky lying at the bottom of the tank two nights ago, very lethargic. I sat there watching her for a while, wondering what was wrong. She didn't come up to eat with the others, so I continued to watch. After a few minutes she moved to the other side of the tank, hid behind a plant, then began what looked like a seizure, for lack of a better word. She started shaking her head back and forth, then rolled a couple times, then went nose down and just lay there. <Yikes!> I thought that was the end, but she was still breathing, and by the next morning she seemed fine. She came up to eat, nibbled on some seaweed, then went on about her business. Again in the evening, she was lying at the bottom, lethargic again, then the same seizure-like activity happened and she sank to the bottom and rested on her side. Same thing today - eating fine in the morning, seemingly normal, then by the evening lethargic, not eating, seizure. She looks fine, physically - she doesn't appear pregnant, did not just have babies, it's just her behavior that is very concerning. Any ideas? <Alarming behavior... perhaps something internal... not treatable> About the tank - I have a 30 gallon brackish (1.004-1.005) tank. Nitrites, nitrates, and Ammonia are all zero, pH is 7.6. In the tank I have Lucky, along with 2 "teenage" mollies, and 5 baby mollies - about 4 months old. There are a couple Anubias plants, but mostly artificial plants. Any thoughts would be greatly appreciated. Everyone else in the tank seems happy and healthy - knock wood. Thanks for you help, Amy <Given your report of the system, conditions, apparent sophistication... health of other livestock, I do think this is "something" anomalous with the one fish... perhaps attributable/label-able as "old age"... Bob Fenner>

Black mollies... Hlth., sys.   11/14/08 hi I have two black mollies and one has white discoloration on him and I understand it could be a fungus and I should do a 50% water change and use Maroxy to help and add a tea spoon of salt to my tank but I'm worried for my other fish I also have guppies and other mollies and platys will the Maroxy or the salt harm them? <Greetings. Guppies, Mollies and Platies will all do well in brackish water. Maintain this aquarium at SG 1.003 (6 grammes, about one teaspoon, or MARINE salt mix per litre of water). Understand this: aquarium or cooking salt won't help. You need to be using marine salt mix, i.e., products like Instant Ocean or Reef Crystals. These not only add salt, but also raise the pH and hardness levels. Black Mollies, and indeed all Mollies, do best in brackish water and almost always get sick in precisely the way you describe when kept in freshwater tanks. http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  Cheers, Neale.>

Dalmatian Molly 11/11/08 I have a Dalmatian Molly and I think it may be pregnant. Another person said it could have bloat, I have never heard that term before. I have tried looking at pictures on line, but my molly is twice the size. Any help would be appreciated. Thanks, Lynn <Lynn, "bloat" is another word for dropsy (technically, oedema). It follows on from organ failure, and is almost always associated with chronically poor environmental conditions. The give-away clue to oedema is that when viewed from above, the scales bristle outwards from the body, so that the fish looks like a pine cone. In the case of Mollies, the most common problem is trying to keep them in freshwater. Mollies rarely do well in freshwater, and unless you're a super-expert fishkeeper willing to carefully monitor pH and nitrate concentration, just isn't worth trying.  When Mollies are kept in brackish water they are infinitely hardier and more easily maintained (aim for around SG 1.003, upwards of 6 g (one teaspoon) of marine salt mix per liter). Next up is diet. Mollies are herbivores, and a very common mistake people make is to give them standard tropical fish food. Mollies should receive such foods only occasionally, a couple of times per week maybe. Otherwise their diet should be algae, algae, and more algae. There are algae-based flakes and pellets on the market, and these are ideal. If given the wrong food, Mollies are prone to constipation, and this causes symptoms similar to oedema. Finally, there's pregnancy. When pregnant Mollies do indeed swell up, but around the abdomen only. The fish should only look "swollen" for a couple of weeks, at which point the fish gives birth and quickly deflates down to her normal size.  Gestation is actually about 4-6 weeks, but only the last couple of weeks cause really substantial swelling. Once you've bred Mollies a few times, it's easy to recognize the cycle. Do read more about Mollies here: http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm  Cheers, Neale.>

Molly skin lesions 10/23/08
Hello Crew,
I would like to express my gratitude for the invaluable resource you provide. My fish also thank you for improving their quality of life.
<Thanks for the kind words.>
I have a cycled 20ga brackish tank with a whisper EX30 filter, a heater, a bubble stone, wisteria, Amazon sword, and horn-wort plants.
<I'm amazed these plants are growing at SG 1.008! Pretty darn salty for most freshwater plants. Are you sure your hydrometer is accurate or you're using it right? Usually freshwater plants struggle above SG 1.005, though there are exceptions.>
The substrate is 5 cm deep fine gravel. I have been testing the water daily with an API freshwater kit and an Instant Ocean hydrometer since adding two Nerite snails and three creamsicle lyre-tail mollies (1 male, 2 females) 2 weeks ago. As expected I needed to change the water daily for the first week to keep nitrite levels under control while the biological filter caught up with the new load.
<Nitrite is toxic to Mollies in freshwater tanks, but seemingly much less so in brackish/marine conditions. That's why Mollies can be used to cycle marine aquaria, something that would kill Mollies under freshwater conditions.>
My values are S.G. 1.008, salinity 10 ppt, ammonia = 0, nitrite = 0.25mg/L(before changes), nitrate = 2.5 mg/L(before changes), pH = 7.8, temp = 79 F.
<Apart from the nitrite, this is all fine. SG 1.008 is actually around 13 grammes of marine salt mix per litre. In all fairness, this is far more salt than Mollies need to be happy, and SG 1.003-1.005 (6-9 grammes per litre) is ample. Your plants should do better at a reduced salinity, and you'll also save money too!>
Thus far all three fish are active, gregarious, and voracious. They even take food from my hand. I am feeding ~50% Spirulina flakes, ~25% TetraMin flakes, ~ 25% freeze dried bloodworms, freeze dried brine shrimp. Both females appear to be quite gravid and I have a 10 ga tank started cycling for the fry.
I have attached a picture of one of the females showing a distressing looking (to me at least) opaque lesion on her dorsum ranging cranially from her lips to the caudal aspect of the base of her dorsal fin.
<From the photo I can't really see much: but it doesn't look obviously damaged. I'd actually imagine this is simply its colouration, and not be too worried.>
To me it resembles the outside of a powdered donut though not entirely white, looking rather flattish and dimpled as opposed to cottony or stringy. The other female has a much smaller area also on her dorsal aspect but it is less pronounced and encompasses a smaller area cranial to her dorsal fin.
<Hmm... do honestly need a sharper image to say anything sensible.>
I have attached a picture of the worst of the two afflicted fish with the hope of obtaining a tentative diagnosis. My fear is that I am dealing with columnaris or a pernicious fungal infection. I do have some background in veterinary medicine (companion animal emergency/critical care) but no practical experience with aquatic critters and I am stumped.
<Well, fungus is pretty rare in brackish water tanks. Finrot and Columnaris are both bacterial infections, but neither is obviously the case here. While you might treat the tank with, for example Maracyn, do take care whatever you use is safe with Nerite snails. Copper-based medications (most anything that turns the water blue or green) can be lethal to snails.>
I don't want to give arbitrary medications based on the somewhat dubious advice of my LFS. Can you tell from the picture what may be going on and advise accordingly?
<Unfortunately can't diagnose the problem, if any, from these photos. Because both fish have similarly placed and coloured "lesions" I'd actually suggest that you're looking at a distinctive colouration of this breed of fish. If the fish are otherwise healthy, and the mouth and fins in particular look clean, I'd be fairly positive about their health, and basically sit back and observe for the time being. But I can't be 100% without a sharper photo.>
<Cheers, Neale.>

Re: Molly skin lesions 10/24/08
Thanks for your response. Sorry the resolution was so poor. Maybe this one is better? (I hope...)
<Yes, certainly sharper. But still not seeing anything obviously "wrong". Yes, there is a white pattern leading back from behind (its) right eye over the shoulder and along the dorsal surface towards the right side of the dorsal fin. But this isn't obviously (to me) a disease as such. One complicating factor is that many "fancy" varieties of fish are extremely inbred, and you can get all sorts of genetic abnormalities. So before diagnosing Finrot or Lymphocystis or whatever, I'd be looking to see if these are merely aberrantly coloured scales or something along those lines. I'd also check to see that scales haven't fallen off. That happens sometimes for no particular reason, though it is more often a sign of fighting or physical damage, e.g., by rough handling or even (failed) predation. Conversely, I'd be looking out for clear signs of ill health, specifically loss of appetite and/or shyness. Livebearers seem (in my experience) to become very withdrawn when ill, and that's often the first sign something is amiss.>
I will take a water sample to the office with me today and recheck the S.G. on one of our refractometers to compare results.
<Have a sneaking suspicion you will be surprised. Swing-arm hydrometers are notoriously inaccurate, perhaps because of friction around the pivot, especially given a build-up of lime or salt. I prefer to weigh out the salt mix, and then use a floating hydrometer to double check the specific gravity. If you haven't tried it out, download my "Brack Calc" tool to see the relationship between salinity, specific gravity, and water temperature.>
Thank you so much.
<Happy to help. Cheers, Neale.>

Dalmatian Molly is sick....I think (Mollienesia; the usual)   10/14/08
I have a 6mos old 10gal tank, water temp stays at 76 F, hardness 180ppm, nitrates ~10ppm, nitrites ~0-1ppm, KH at 50ppm and PH 6.9-7.2
<Way, way too soft and acidic for Mollies. Do understand that Mollies will not, repeat WILL NOT, tolerate anything other than rock hard, alkaline water. We're talking pH 7.5-8.5, 15+ degrees dH. Arguably -- and it's a VERY strong argument -- they are best kept in slightly brackish water, around SG 1.003 to 1.005. Moreover, they are VERY INTOLERANT of nitrite, so if you can detect ammonia or nitrite, and you aren't keeping them in brackish/marine conditions, that's as good as signing a Death Warrant. In any case, the tank is too small for Mollies. Even a tank 3 times this big would be marginal. They are NOT easy fish to keep, hence the constant flood of messages to WWM about sick Mollies!

We use an AquaClear 3 stage power filter. We have one each of the following; neon tetra, white cloud, sunburst, Dalmatian molly, algae eater.
<One Neon? One Minnow? These are SCHOOLING fish, and MUST be kept in groups of six or more. Please please please read up on the needs of your fish. I wonder what the "algae eater" is? If either Pterygoplichthys ("Plec") or Gyrinocheilus ("Chinese Algae Eater") you will live to regret this purchase. Both are huge animals, and Gyrinocheilus famous for being nasty, aggressive fish when mature.>
The molly was the last fish we added. At that time the water clear, we added the molly..loved the
algae on the shells. the a small algae bloom appeared. Added Algaefix and within 3 days the water was crystal clear and ALL fish were happy.
<Algae is not a problem as such. Do understand it's TELLING you something about the tank. Don't "fix" the algae, but instead concentrate on what might be amiss. Is the tank getting direct sunlight? Is the water stagnant? Are there too many fish?>
We recently moved (next door) so I took the tank down between a half and 2/3, so I could carry it over. Then refilled the tank. Added a little aqua plus which we used when we originally setup the tank. Since the move a very large algae bloom began taking over the tank, green algae. I added Algaefix again. I have noticed though when I add algae fix the molly becomes unhappy and camps at the bottom of the tank.
<Algae is what Mollies eat. They like it. Indeed, they're healthier fed on algae than flake! Besides, anything poisonous to algae will, at best, cause conditions to decline as the dead algae decays. At worst, the Algicide will stress your plants and irritate your fish. There is NO GOOD REASON to use algae killing medications, and plenty of excellent reasons not to.>
So rather than keep up those treatments I have been doing weekly 25% water changes and cleaning the filter each time. The molly seems to like the water adds, very active.
<Yes; they like clean water. Between water changes the water quality drops, and the Molly gets stressed. Do a water change, and he peps right up.>
But when I treat the algae it seems to dislike it. This has been going on now for a month. This past weekend I decided to do about a 30-40% water change, tank was VERY cloudy with algae. I also added cycle to the tank to try and address any issue with the bacterial cycle. This was about 3 days ago. Today the molly is staying at the bottom and trying to lay to it's side, when it begins to tip is catches itself and tries to resettle again, sometimes it goes all the way on its side, but rights itself each time if it begins to drift upwards. I also notice it occasionally tremors as it camps on the bottom trying to get settled.
<This is something akin to "the Shimmies", and a VERY good sign that your Molly is not healthy.>
All the other fish are very happy, except the molly. The water is still cloudy but much reduced. I changed the location of the tank. less sunlight exposure and leaving the light off most the time...Bottom line I don't know what's going on..very new to this and could use your guidance.
Cycle, Algaefix and Aqua plus are the only chemicals I have used.
<Lay off the chemicals, and hit some books instead...><<Bingo! B>>
We use TetraColor tropical flakes as their food...
<Mollies are herbivores and need algae-based flake foods. In any case, colour enhancing foods are much misunderstood and best ignored in favour of varied, balanced diet.>
Thanks in advance for any help!!!!
<Hope this helps! Please review in particular: diet, water chemistry, water quality. Maintain your Molly in a tank offering what this species need, and he should be fine. At the moment, things look gloomy. Cheers, Neale.>

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