sick mollie

Question
we have been testing the water regularly and the amonia,nitrite and nitrateare all 0.. It was his swim bladder he died and the other mollie is fine..
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-----Question-----
I bought 2 mollie's yesterday and one of them was very inactive after a couple hours and this morning he just sinks to the bottom of the tank and flips upside down when he trysto swim?? Now the other mollie is slowly starting to show the same issues?? Can you offer any opinion of what this might be???
-----Answer-----
Hello,
How long's your tank been set up? If it is under 4 months it is not mature enough for Mollies. Did you cycle the tank? If not, there will probably be levels of ammonia and nitrite in the water, which are poisonous to the fish in the tank. the best thing to do would be to take the Mollies back to the shop while you sort the tank out, otherwise they could die.
I strongly recommend buying test kits for ammonia, nitrite and nitrate. The ammonia and nitrite should be at 0.0 all the time, as it is, as I stated earlier, poisonous to the fish. Do 20 percent daily water changes until they are 0.0. The nitrate is safe at levels under 20ppm. Live plants will help lower it.
Feed the fish a varied diet of live and frozen bloodworm, brineshrimp and daphnia, as well as boiled cucumber and shelled and boiled peas in addition to their regular flake food.
When the water parameters are right they should be ok, if they have not been poisoned by the ammonia, but if it is swim bladder problems, which cause them to swim up side down, there is no treatment available. You would just have to wait and see if they are ok, while doing regular water changes.
Good luck,
Kathryn

Answer
Hi,
A am sorry he died.
It is good that the ammonia and nitrite are at 0.0, but the nitrate should have some reading, not 0..?
I think the best thing to do now would be to give them a varied diet like I stated above.
I hope the other fish are ok.
Good luck,
Kathryn