Buzzyw0n

I just got a new balloon molly today and he is beautiful. But my older female balloon molly keeps on chasing him and like nipping at him. Does this mean she is teritorial? Or is it some kind of breeding?

TFA101

she is being territorial. this is common with newbies. They are establishing a pecking order at the moment and this can be in the form of aggression. In other words, everybody is settling out who's boss in the tank and teaching the new guy who the alpha (fe)male in the tank is. I wouldn't worry too much unless it becomes constant.

Iron waffle

Yeah, it's common among livebearers. If it persists, it usually works to isolate the problem fish for a little while, rearrange the tank a bit and them put him back (it sounds crazy, but it almost always works)

aquarist48

If you can rearrange the tank without removing the fish it would be a lot less stress on it.

Buzzyw0n

thanks