aggressive molly

Today I saw my female chocolate molly hiding a lot and not coming up to eat but looking around the bottom for food. I then noticed my male dalmation Molly really going after her and nipping at her. That was the most agressive behavior I have seen from him before. He's not trying to breed but biting her fins and aggressivly chasing her until she hides. He is fine with every thing else in my tank but not her. When I first got those 2 mollies they were fine with each other until my female dalmation molly had fry. After that day which was about a month ago, if my chocolate molly got close to him or the female dalmation molly he would chase her until she swam off. Now he won't let her stop hiding. The male dalmation doesn't care if any fish go near him other than my female chocolate molly. I feel really bad for her. Is there anything I can do to help her? Just to clarify the molly who had fry yesterday was not my dalmation female or the chocolate molly but a different orange molly.

Separation is the normal response, if you do not have another tank, maybe a tank divider would work.

I'm not sure if a tank divider would work because my tank has a bunch of plants and driftwood to the point where it would be really hard to get a divider in my tank. The only other tank I could put her in is my 10 gallon fry tank but there are 1 day old molly fry and I'm afraid she would eat them.

Oh dear, another one misbehaving!
Please can you post the tank size, fish species with numbers, and test results. We can then check for any additional stressor that may be contributing.
I haven't kept mollies for a long time, maybe @emeraldking could offer advise?

Luckily the balloon molly is behaving now and now it's only my dalmatian and chocolate molly misbehaving. I have a 29 gallon planted tank with lots of driftwood and hiding places. I have 2 upside down catfish, 2 guppies, 6 mollies (2 males and 4 females), 1 platy, 8 cories, and snails. I know my tank is overstocked but I am getting a second filter and I do 50- 75% water changes weekly. My water was tested yesterday at my LFS and my water parameters were 0 ammonia, 0 nitrite, 7 nitrate.

Retired Viking said:

11 is not bad at all, please try and post a picture of them when you have them settled into your fry tank.I had to try out the new one

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I got some pictures of them today. Sorry they are pretty blurry.

corylover5 said:

I got some pictures of them today. Sorry they are pretty blurry.

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Awww so cuute

Change in behavior is something that can happen. In this case aggression. If I've read it correctly, the aggressive behavior happened to each fish but not simultaneously. It could be a hierarchy thing. Each one tries to see who's the alpha within the group. They'll test eachother. This can happen in a group. Will it remain? Could be but doesn't have to be. Most of the time once they know their place, the peace will return.

Thanks. The Dalmatian molly is starting to stop chasing her. She started coming out from hiding now.