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FAQs on the Molly Disease: Genetic

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

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

IF at all possible; buy from locally produced sources. If not, then from Florida fish farms... lastly from far east importers

Too in-bred, overly-stressed specimens die like proverbial flies

Balloon Belly Molly problem 7/16/11
Hi! I have been reading your info forever, now I need your help!
I will attempt to describe the issue as well as possible. I've had balloon bellied mollies for 8 years and I'm stumped I purchased this BBM over a year ago, she was a light gray and white mix, full size and seemingly healthy. I never had a problem with her. She had a couple sets of fry within the first few months I had her and she and her fry did well and were healthy. Shortly after I removed the males from that tank and there were no more fry from her. In the past 6 months she's been... Changing. She is now twice the size of all my other bbm's, and her front half has turned orange.
Vivid orange. But the back half of her is still this gray white color. The scales on the orange half are large and almost look like they bubble.
<I see this in your photos>
Lately I've noticed she'll get a hole through this area (almost thought it was an ulcer) but it doesn't seem to bother her and it'll heal up and then I'll notice another. But she is not bloated or just swollen. She has actually grown. Example- her mouth is twice as large as the other fish. She could eat one of my frogs' crickets if she wanted! I've researched everything. It's not a tumor. It's not hole in head disease. I can't figure it out. She honestly looks... Old. My water levels are great and none of my other fish have problems. And she is still as energetic as always. Eats well. Sometimes I wonder if she's going blind though. Anyhow. Her body looks like the front half belongs to a different fish. Changed colors, 'blew up', scales are huge and almost bubbly. They are pineconing on the orange half. Over night last night the top 'irregular' half of her has started to turn pinkish white and her scales look like a finger that's been in the water way to long. Hoping you can help! I have included some cell phone pictures, sorry for the quality. Thanks!
Taryn Phillips
<This looks to me like some sort of "Elephant man/fish" syndrome. A genetic anomaly. Do any of this fish's young show these traits?
Bob Fenner>

"I am elephant molly fish"

Re: Balloon Belly Molly problem 7/17/11
Thanks for the quick reply!
<Thank you for sending in such an interesting post Taryn>
To answer your question, no, none of her fry are showing signs of this. The ones that are still in my care are beautiful white with very well shaped bellies.
<Ahh, more weight to the thought that this is a genetic anomaly>
However at about 8 months old now they are not quite the size of my other adult Balloon Bellies, but I have noticed they are still growing. I have wondered about some sort of Elaphantitis,
<Mmm, well, this condition is mainly caused by Nematodes... a type of filariaisis, blockage of circulation... I suspect summat else here w/ your mollies>
and it maybe be something that will show up in her fry in a couple years. I had a recommendation to take her to a biology or zoology lab at a local university after her passing. What are your thoughts on this?
<A good idea in my estimation. This "strain" might prove of some good use in study. BobF>

Sick Molly Fry? 2/4/11
Hi Neale/WWMC,
I have 8 black Molly fry about 8 weeks old. The 4 largest have gills that stick out. It actually looks like the white lining of their gills are sticking out. Their gills are not red. They show no other sign of being sick/stressed etc.
<Yes, I think this is simply a birth defect -- missing or shortened gill covers, so the gill membrane and/or gills themselves become visible. Not uncommon with Mollies and other livebearers because they tend to be inbred: people buy a brother/sister pair from a pet shop, they breed them, and then those are taken to a shop, and someone else buys a pair from that batch of siblings'¦ and so on.>

They eat normally, swim healthily, have no other marks or abrasions and do not rub their sides/Gills on rocks or driftwood.
It's like the inside of their gills grew bigger then they should have.
They're a white/grey color.
Have you come across this before?
Because I have searched high and low and can't find a similar case. No picture I've seen resembles this. I've tried to get a picture but they're so small as is, it's hard to get a pic. Doesn't look like gill disease, doesn't spread like fungus, doesn't look like parasites.
Any suggestions? Any idea of what this could be?
My tank is slightly brackish 1.002
Ammonia, nitrate, nitrite all at 0
Water is hard above 8.
Shouldn't these be ideal water conditions for Mollies?
I do a 20% water change each week. Sometimes a little more even!
Any input would be great thanks!
<If they're fine, you might leave things be. Or you might elect to destroy humanely any deformed ones -- 30 drops of clove oil in a litre of aquarium water will do this very quickly. That way any that remain and breed should at least lack this deformity. Try adding another Molly from another shop to the mix -- often this perks up the gene pool dramatically, and you get much better fry. Cheers, Neale.>

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

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

Molly and Platy "issues"   6/22/08 Hello again And once again I must extend my gratitude for all the support you lend to us "novice" fish-keepers and our finned-friends. <We're happy to help.> To start I am attaching a picture of my mama speckled molly....As I hope you can see, she has developed this "wart-like" growth above her eye. It has gotten a little bigger over the last few days but her personality hasn't really changed much. She is still eating like a champ but she might not be swimming around as much as usual, its hard to tell now that I have taken the male molly that used to chase her daily out of the tank (for different reasons). My water parameters all check out (0,0,10) and this started before I added my most recent additions. I did lose my 2 German rams over the last 3 weeks for unknown reason (I suspect its because my husband accidentally unplugged one of the heaters twice overnight when he turned off the light and since they are so sensitive the 5 degree dip in temp (usually hovers around 80 but went down to 75 both times) because they each passed around the times that this happened. At any rate, back to the molly...What on earth do you think this is? Should I QT her? How do I treat it (if I can)? Do I need to worry about my other fish in the tank? <I'm not 100% sure, but this looks a lot like Lymphocystis. This a non-contagious (or at least only weakly contagious) viral disease caused (almost certainly) by environmental issues. The bad news is that it can't be treated. The good news is that it doesn't kill fish and usually goes away by itself (though this may take months). No need to quarantine her. Strong need to review the environment, for example is the carbonate hardness nice and high, are you using enough marine salt mix, does she get enough algae to eat, and so on. All the usual Molly stuff. In any case, the "growth" is certainly some sort of cyst, and as such not likely to be either treatable or dangerous.> My second issue is housed in my QT tank (my main reason for not putting my molly girl in there just yet) I emailed you guys about this problem a few weeks back and didn't really get an answer (I think it was Neale and he sounded just as baffled as I was) I have had this female platy in there for many many months now (I'll attach a photo of her too just in case you can see something that I can't) and she has lived though numerous treatments of every medication known to tropical fish (mainly because my QT tank is the only QT tank for both mine and my dad's tanks and every sick fish is treated in there) Her spinning/flipping/darting has never improved nor gotten worse. I am still stumped on what to do with her and I am really tempted to just put her back in my main tank so I don 't have to continue keeping this tank running for her. (not that I mind all that much but I am sure she is bored in a bare tank all by herself.) <She looks fine.> To repeat the story, It started at least 4-5 months ago about a week after I got her home from the fish store (okay, wasn't really a fish store...I'll admit my momentarily lapse of judgment and admit I bought her at W**-Mart...Not the smartest thing, I know) ..I noticed she was having trouble staying upright and upon closer inspection I noticed that one of her gills not only looked a little torn but it looked like it had a severe internal hemorrhage. She would swim erratically, dart, spin, hide, and for the first few weeks wouldn't eat. I thought she was a goner for sure. Well, after a while her gill healed, she began eating and swimming around but, she would still have frequent episodes of spinning, flipping, swimming on her side and basically freaking out. They don't last forever but do happen often...she can still swim normally but for the most part just hangs out in the corner. Her color has gotten lighter but I don't know if that just because I keep the tanks lights off the majority of the time or what. I am hoping that someone has some idea what this is, if I could return her to one of my main tanks, and/or how to treat it. I used to think it was "whirling" disease but considering she isn't a trout and she has lived so long I don't think that this is the case. <Quite so.> I have also considered parasites but like I said, she has undergone every treatment (including every parasite treatment) and still spins/flips/darts. She has had some noted improvement and that I think occurred around the time I was treating one of my dads molly's for parasites but I can't say for sure. Any advice on these matter would be greatly appreciated. <Absolutely no idea what this is!> Respectfully, Grace <Don't think anything too serious, so provided all else is perfect, would leave this fish figure out their own problems. Could be genetic issues for example, or exposure to heavy metals at some point in their life. Variety of things. Good luck, Neale.>

Defective Balloon Molly    1/14/07 I recently purchased a balloon molly and it has been acting a bit strangely for the past couple of hours.  It does seem to have the best control of its swimming and often does "barrel rolls." <Eeee, not good... evidence of "swim bladder damage"... can be from a variety of causes...> It sometimes swims on its side and often lodges itself under the aquarium decorations upside down. The times that it does decided to unlodge itself it obviously has no control over it movements and tends to crash into things.  I am aware that balloon mollies aren't the most graceful fish and do tend to behave "strangely." <Mmm, yes... part of their "mutant" price> This behavior does seem to be too strange even for a balloon molly and I am afraid that it will hurt itself. I know that these fish often have problems with swim bladders, and I also know that they can catch the whirling disease (my fish's movements aren't spiraling, he just does barrel rolls.) <Mmm... not so much the bacterial mediated version of this label...> I was just wanting to know how to distinguish the two, assuming that the fish's problems are one of the two.  My other fish, which includes a balloon molly, are doing fine. I had a local pet store test my water and all levels (nitrites, nitrates, ammonia, pH and hardness) were all in check. Thanks, Lauren <Mmm... if this fish/specimen is doing this anomalous behavior a good deal of the time... I'd isolate it... not so much for fear of pathogenic disease spread (which I doubt is an/the issue here) but for the other livestock not being overly-stressed... Ultimately, euthanizing this fish may be the humane route to go. Bob Fenner>

Molly Crossbreeds and susceptibility to white spot    1/5/07 Hello from the middle of the UK <And hello from Chicagoland, Illinois, USA!> Firstly, your site really is a fantastic resource, many thanks for the hard work you must all put into it. <On behalf of the WWM Crew, thanks for the kind words.> I have found different websites have slightly varying opinions on the finer points of keeping tropical fish... <...there really are lots of views out there.  Of course, there are some concrete basics that cannot/should not be varied, but many things are debatable...lots of differences of opinion, even amongst crew members at times...> ...your site deals with this so well as the answers in the faq's come from different people as do the questions, it's very informative, thanks again. <Glad you find it useful! I am always looking things up on the site - it's how I've learned much of what I know about the hobby.> Having prostrated myself at your feet and declared myself "not worthy" :-)..... <Well, you don't have to go that far!! lol...> I have a 150 gal tank with 2 female Bettas, 1 Plec, 1 Algae eater (long thin light orange sucky fish, not sure what to call it really)... <another type of Pleco, perhaps? Any pictures for identification?> ...7 tetras of varying types, 1 Lyre tail molly and 12 fish that came out of the Molly, I think they may be crossed with a Guppy we have in our other tank... <crossbreeding between livebearers can, and does, indeed happen> ...(we moved her and some of the offspring, she is getting quite big and the kids were taking over the tank). <Yup, livebearers can/will do that! I'm amazed they haven't taken over the planet with their reproduction rate...> Water is at 28.3 deg C +/- .2... <This is the high-side of OK for most tropical fish, but good for the Bettas...> ...ammonia 0, nitrite 0, nitrate around 40ppm... <MUST reduce the nitrate levels...20 ppm is as high as they should be.> (most of the time) ph 7.8 constant. Filter is an Atman 882, it's an in tank filter, housing a heater, 2 compartments holding bags of different filter medium and a pump, in that order as the water flows through. I do a 10% water change/clean every week and add a little stress coat type treatment (Nutrafin AquaPlus) each time to the fresh water to remove the chlorine and help the fish, I normally age the new water for 24 hrs before doing the change and add a little AquaPlus (20ml) to the tank. <Your water change schedule generally sounds OK, but since those nitrates are so high, I would recommend doing a 10% change 2 times per week, until the levels fall under control.  They really are too high and are likely stressing the fish, causing them to be more susceptible to disease.> The water from my tap is quite high in nitrate (around 40ppm) so 1 of the bags in the filter contains "Nitrate Sponge" to help keep the nitrate at an acceptable level. <Well, there's the problem, then...if you keep doing water changes with this water, the nitrate levels likely won't drop.  I'd recommend looking into a RO/DI unit, or at the very least, a DI product such as this one: http://www.aquatichouse.com/WaterPurifiers/tapwaterfilter.asp The RO/DI unit will cost you more, but will save you money in the long run, as the filters don't have to be replaced nearly as frequently as the Aquarium Pharmaceuticals Tap Water Filter product.  I don't know if they'll ship to the UK, but I am a big fan of www.airwaterice.com for RO/DI units. I'm not familiar with the "nitrate sponge" product you refer to, but it clearly isn't working.  I really suggest a water filtration system.  Everything else you describe seems great.> Questions: Can a Molly cross breed with a Guppy? <Yes.> The offspring certainly look like that is the case though there was also a male Swordtail in the other tank when she gave birth (She has also had normal Molly babies before and after this bunch arrived). <From my understanding, all livebearers are capable of cross-breeding. Might want to consider just housing a single sex, if you want to keep all these different species.> A quick aside here, she also gave birth to a Platy! <Without a platy parent?!> And we don't have any, well we do now! <OK- I'm confused a little about that one...> Why are these cross breeds so susceptible to whitespot (The pure Molly is fine as are the rest of the fish)? <I am by no means a geneticist, but my general understanding is that too much genetic variation causes all sorts of problems, including a weakened immune system.> If the nitrate level climbs above 50ppm they start breaking out with it,... <Nitrates really need to be between 0 and 20 ppm...> ...which is fine when I spend a lot of time watching them as I see the first spots and drop in some of the stress coat stuff and check the nitrate levels straight away and the whitespot goes in a day or 2. HOWEVER, if it's Christmas and I don't pay enough attention, they get in a hell of a mess in a very short time and it's out with the blue stuff (Waterlife Protozin) to fix them. <Do read here for some helpful information on treating ich.  Keep in mind that the ich parasite goes through various life-stages, and truly the only way to get rid of it is to run the affected tank fallow for at least a month... http://www.wetwebmedia.com/FWSubWebIndex/fwich.htm > Probably worth mentioning the fish in question are now at least 4 months old, maybe more.> Any ideas? The best I can come up with is that it's a genetic failing, but I wanted to check it's not something I am doing wrong, I'm not sure they like it! <It is likely a genetic weakening, and these fish will likely always be more susceptible to disease than their "purebred" parents.  The one thing you can do is to lower your nitrate levels - that's about the only problem I can see.> Many thanks again John <You're welcome. Get rid of those nitrates and you're fish you all likely be more healthy.  Best of luck, Jorie Re: Molly Crossbreeds and susceptibility to white spot (Now about Nirate levels)  1/5/07 Hi, have replied with the previous message and comments below so you know what's going on. <OK, sure!> Firstly thanks for the info, a brief overview of your reply would be that I need to get my nitrate levels down. Great, I have something to do that should fix the problem so... 3 reasons for my reply: 1) Many many thanks to you all 2) Discussing reason 3 may help others with their searches when this message goes into the site 3) I'll be as brief as I can....... <(1) thank you,(2) this will be posted on our FAQs, and hopefully others can benefit from the info. also, and (3), no worries - I can be long-winded myself!> Up until now all the information I have read and been to me given about nitrate levels has been that they don't matter too much, and yet "Graham T" says 20ppm Nitrate is good, any more is bad, 60ppm a big no no... <Graham is one of my fellow volunteers; for some reason, I think his name got attached to our general "crew" e-mail box.  In any case, my humble understanding of water chemistry is that 20 ppm is not "good", per se, but on the high-end of acceptable.  In an ideal world, nitrates would be at zero, but that's pretty hard to achieve in reality. If the reading is 20 ppm, I do a water change, but I understand that in your case, since your tap water is coming out at 40 ppm, this really won't help.> ...and yet when I ran up my first tank a year and a half ago, I took a sample of water from the newly cycled tank to my local shop and they tested the water and did not comment on the nitrate being around 50ppm. <This is precisely why I test my own water and do independent research.  I can't tell you why your fish store wouldn't advise you the same way, all I can say is that my own readings, research and experience have all led me to the conclusion that FW nitrates must be 20 ppm or less for the ultimate good-health of the livestock.> The water from my tap has a nitrate level of 40ppm!!! <I remember - I was shocked when I first read that!> so my frequent water changes are just making matters worse. <Well, I wouldn't say worse, but it certainly explains why your last reading was 40 ppm...> I shall put my hand in my pocket and buy a water purifier. <Reverse osmosis/de-ionizing units can be expensive, but well worth it, in my opinion.  We had a problem with high phosphates in our tap water, which is what led us to purchase ours...our fish have never been healthier.  Plus, there's a drinking water switch, so you may be able to benefit from that, personally, as well!> But, a couple of questions: A quick search of WWM shows that you all think that nitrate levels are important, how come I had so much info that said otherwise? <"So much" contrary info., or just what your local fish store folks told you? Again, I certainly can't comment on why others say what they do, but I can tell you that most, if not all, reputable research in the hobby shows that nitrates, while not as toxic as nitrites and ammonia to fish, certainly aren't good and should be as low as possible...> I am beginning to thing my beautiful male Betta died because of the high nitrate levels, I won't replace him until I have got the nitrate down, he was more of a pet that a pretty fish in a tank, real personality, sob sob etc... <I agree with you - I've got three Bettas (two males and one female, all separate, of course), and they are my favorite fish.  So much personality, and beautiful, as well.  I can't say that the nitrates killed your Betta, but they surely didn't help.  Another common problem with folks keeping Bettas is not keeping them in a min. 2-3 gal. filtered tank, with a heater set to a constant 80-82 degrees F...I'm sorry you lost your little friend.  Once you get your RO/DI unit, and a suitable tank for the Betta, you will be all set, as they are very low maintenance once these general requirements are met...> sorry, had to let it out somewhere :-) best to do it where I maybe understood. <Ask my boyfriend - I am the nutso-save-all-the-Bettas-in-little-cups-in-PetSmart lady - I'm in the process of writing a simple how-to-care-for-your-Betta article.  It's one of my passions! Long life the Bettas...I can keep going for ever:-) > Second and maybe even more importantly, myself and my family (and everyone else in the town) are drinking tap water with a nitrate level that makes fish ill. Is this bad for humans?????? <Well, I'm not a doctor, but I can't imagine it's good.  Again, if you invest in a RO/DI unit, I would look into the drinking water attachment...> Finally a note for the google search to help others... " High nitrate levels in tap water " :-) <Thanks - will pass this along.> My complete thanks to you all John <You're welcome, John.  And, your P.S. re: a FAQ on sending pictures - I am forwarding that along to Bob Fenner himself.  I'll happily admit I am not a computer junkie, and as this is Bob's site, he's the best one to help you out on that note. I'm sure he'll appreciate the advice/suggestion.  Best regards, Jorie>

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