VERY aggressive molly

[cyrix]

I had three mollies I added to my tank a little bit ago and at first they were all fine. One of them was pregnant, and she sadly died last night. I now have one white/albino one, and a black one. The white molly is extremely aggressive with the other molly, all 8 serpae tetras, and my angelfish (he's still a little guy.) I've taken it out of the tank and put it in my isolation/hospital/whatever tank.

I'm not really sure what to do... I feel it contributed to the death of my other molly because it was chasing it all the time, and I really don't want it to over stress the last molly or my serpaes or angelfish....

So any advice?

EDIT: It's a 30G tall tank.

[Dave66]

It's unnatural for mollies to be in such small numbers, as they are a group fish, and travel in large aggregations in nature. It's so unnatural, the molly responds by chasing every fish in the tank, because they run from him.

If you have the space and the tank is completely stable, next time get eight or 12 mollies or more so you'll see natural behavior.

Dave

[cyrix]

Huh. Thanks for the reply. I was told by a few people here my stocking would be ok. Seems that's not the case. Thanks.

[thrakuarium]

At the very least the female to male ratio should be 2 to 1. I am assuming the molly you removed is the male. If he was down to just one female molly, she was probably stressing from all his attention and hiding which left him frustrated and resulted in aggression toward the rest of the tank. I agree with the other post on increasing the number of mollies in the tank if you have room. I think adding 3 more females for a total of 4 females and the 1 male would probably work. On a side note, the angelfish can get territorial and semi-aggressive. Just something to consider for the future.

[cyrix]

At the very least the female to male ratio should be 2 to 1. I am assuming the molly you removed is the male. If he was down to just one female molly, she was probably stressing from all his attention and hiding which left him frustrated and resulted in aggression toward the rest of the tank. I agree with the other post on increasing the number of mollies in the tank if you have room. I think adding 3 more females for a total of 4 females and the 1 male would probably work. On a side note, the angelfish can get territorial and semi-aggressive. Just something to consider for the future.

I had three females in the tank if that helps.

[Little Embers]

Fish are all individuals and your molly may just be one of those with an aggressive nature, you may need to return him if possible to maintain peace in the tank.

[cer]

I agree with little embers.

[Wiggs]

I agree with Dave, nearly any species of schooling or group fish will react in strange ways when put in small numbers.