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I'm a huge fan of molly fishes however the problem is this. They dont seem to survive!

if i put in other fishes maybe even less hardy ones they seem ok and have no problems staying alive.

but the mollys slowly drop off.

the tanks been established about 2 years now and i've tested it and tested it again the water is fine. i've taken the water to LFS adn they're sayin it fine.

could it be any of my other stock doing something? unlikely as the dead fish seem to b intact and no body parts missing.

the last one though seemed to have swimbladder - where the fish is upside down and didnt have much control in putting itself upright, hten the next day it was ok and i saw it swimming around but it died later on that night.

my stock
2 male guppys *fairly new*
4 neons
1 peppered cory
1 golden loach
1 clown loach
2 silver tip tetras
2 otto's

i did try to do a planted aquaria recently and that did lead to a bloom in algae but thats a different problem all together. i've tried puttin in a course of melafix hte filters clean but still no idea y its only my molly's that are dropping...

i have had many molly, i love them too . i have now 3 females, 3 males, 4 older fry, and about 20 new fry (just born last night) i have only lost i female the hole time i have had fish. but males..thats a hole other story, umm... 5 males i think. i dont know why but i have bad luck with the males. try getin some girls, for me they do soo much better.

Some mollies do much better with a little salt in the water, which is presumably something you cannot do because you have corys in the same water.Sometimes their longevity and disease resistance is affected without it.This can sometimes be especially true of some rather overbred strains of molly, whos disease resistance may be low anyway.

My question is ... how big is your tank ? I've had the exact same problem and what I found out is that my mollies for whatever reason cannot survive in my 30 gallon tank. If they are in the 10 or 20, they are just fine but as soon as I move them in the 30....

Just my 2 cents.

what is the temp, about 80 is ok for mollys in my tank

one possibility is at lfs, they might keep mollies in water that is slightely salted. and the fish adjust to this by adaptation and maintain a body salt concentration isotonic to that of the surrounding (same salt concentration in body as water), i remember fish being osmoconformers. so when you suddenly reduce the salt concentration in their environment, ie put it in fresh water. water is going to move into the fish by osmosis, from high osmotic pressure of tank water to low osmotic pressure of fish. hence fish might get excess fluid in its body and causes something similar to a swimming bladder problem.

never actually seen the process happening my self, but i would assume that is the case