Mollie Questions

Question
Hi, I have two questions about my Mollies. My tank is ten gallons with one spotted Cory catfish and a white female Mollies. The water is clean and ammonia free.

#1: My white Mollies likes to sit up by the heater at night, but swims around during the day. I keep the aquarium light on during the night, but turn it off during the morning and part of the afternoon. I'm not really worried about what my Mollies is doing, I'm just wondering if she is trying to sleep. Do you have any recommendations as to when I should turn my light off?

#2: About a month ago, one of my dalmatian Mollies gave birth, (she has passed away). During this time we were having some problems with ammonia because the tank was just set up only a few weeks before. We managed to save five of her fry and they are all doing fine in an incubator. However, I have one fry who has a swimming problem. His tail is bent up slightly, and he can't keep himself up. I noticed when he was younger that the bones in his tail were bent. He doesn't have trouble eating, but I'm concerned when we let him out of the incubator. I'm worried he will be picked on by the other fish. Will he "grow out" of this problem, or will be he be like this all his life? I have noticed a small improvement on his swimming since he has gotten older. Thanks for your help!

Answer
Hi Shelby,
Its best to keep your fish on a regular light/darkness cycle. Try to give them about 10-12 hours of light each day and let them have darkness at about an equal amount of time. Sounds like your mollies prefer to sleep near their heater. Maybe its comforting to them.
You can also turn off their lights for a few hours during the day when you aren't home or not around to view your tank. As long as the fish are not plunged into complete darkness they will be fine.
With the second question. I'm sorry to hear about the little molly fry. It sounds like he has a genetic deformity. Fortunately this doesn't mean that they will live a miserable life. I've had many fish who were born deformed and they grew up to live quite a decent life. Whether or not he will be picked on just depends on individual circumstance. If he is slow with swimming he may be picked on. But you never know till you try. Bent tails and other deformities can also be caused by vitamin C deficiencies and  lack of swimming space. But these are just possibilities. More likely it could be a genetic disorder.

With your little molly you'll just have to wait and see. I've never had the heart to euthanize deformed fish unless their health or quality of life is severely affected. If they can still eat and swim comfortably, they should be fine. He may improve on his swimming as he gets older but I don't think his tail will improve.

But best of luck on the little guy and I hope this helps!
Happy holidays,
Karen~