Mollies dying

[davidsnew]

All of my water readings are excellent, 30 gal tank, change approx. 40% every 6 to 8 days,

We bought 4 mollies about 8 months ago. Two of the original 4 have survived and appear to be doing quite well. The female has had several birthings and from those we had 20 to 30 survive past the 30 day mark. Over the next few months we started to see a pattern develop. Their spine would start to kink to one side or even down at a point about 2/3 of the way back from the head. after that starts to happen they will die with in the next several weeks.

Has that sort of thing happened to anyone else out there?

[Tetratastic]

That's not happened to me, but I've heard that fishy TB can sometimes cause spinal deformities, other than that, I wouldn't know.

[davidsnew]

I certainly hope that is not the problem, but I do think that if it were TB, the other fish in the tank would be experiencing some sort of symptons.

I think!!!!

[KateA.]

Hi, found this board recently and I love it!

We used see this quite a bit at our pet store with the livebearers. We moved our store last August and got the Marineland retail system for our fish and are now able to keep them isolated from the rest of the fish. We keep them in a bit of salt and do very frequent water changes with R. O. water. So far, cross your fingers and knock on wood, we haven't seen much of it. We've been having other mysterious outbreaks, but nothing we can put our finger on.

[JeffP]

There was an article on mollies in TFH magazine where the author discussed the kind of condition you mention. If I recall, the article was in the last 6 months (I think). Also I can't remember what remedies were recommended, but I think one of the author's points was that mollies come from a wide variety of environments but some mollies benefit from conditions approaching brackish. My brain is in a fog today since I was up late last night watching Syracuse Univ. win the national NCAA Championship. GO SU!

Anyway, I will try to see if I can find my copy of the magazine. You might try searching some local lfs stores with back issues lying around. TFH doesn't have much of an online presence.

JeffP.

[Faramir]

Salt may help some mollies, but I don't quite see the reasoning behind RO water - high TDS is generally the way to go.

What is described does sound like TB. It's possible that unsuitable water conditions - low TDS, acid water - might contribute to weakening the fish, which is why the other species are OK. However, I usually see skin problems in livebearers who are compromised.

[OrionGirl]

Just a guess, but it could be a problem with inbreeding. Most fish can tolerate a high degree of inbreeding before deformities start popping up, but if you have some fish that have been line bred for multiple generations, it can happen. I'd try getting another black molly from a different source and see if that changes things.

Another option is low trace elements. Young fish contain no bony parts, just cartilege. As they mature, they need more calcium so they can begin developing bony structures. The spine is the first part to calcify, so would show the first problems. Whirling disease prevents the calcification of the spine in young fish, resulting in deformities. While you definitely do not have whirling disease in your tank, a deficiency in calcium could have similar results.

[thom336]

i would agree that it is a genetic problem, and one that is unfortunately becoming all to frequent with livebearers these days. for good quality stock, your best bet really is to goto shows or get in contact with clubs and specialist breeders, as they would not sell substandard stock as they have a reputation to uphold. i think the trade in wild livebearers is going to have a peak soon, as people will soon realise that quality is best.

[Harry Tolen]

I would tend to agree with OrionGirl's second point more than her first. The likelihood that your mollies' offspring are the first generation to suffer from such severe genetic problems is low, but the odds that you are raising them in conditions that are not conducive to healthy growth is somewhat higher, especially since mollies are brackish to marine fish. I'd try buying some marine mix and giving them an environment with levels of the various trace elements more like what they would get in nature. Be aware that there are lots of other tropical fish which do not appreciate salt in their water at all; if you have any of these you might want to move them to a separate tank.

[davidsnew]

Sorry I'm so late getting back to everyone. I have been away from the computer. I really appreciate the input. I am at a loss as to what is happening.

I don't really think that it is water quality unless it is a lack of salt. I am somewhat skeptical about that being the problem, however not certain that it is not.

Thanks for your responses and email me or post it if you think of anything else.

[JP457]

I read somewhere that in guppies, the fry can develope crooked spines if they dont recieve enough nourishment when young. Mollies anr different but it could be the same thing.

[Faramir]

Out on a limb here, but how high is your GH?