My danio's have gone crazy. Usually they swim around the tank and chase eachother around. There is one that is bigger than the rest and she (I think the big one might be a girl) dominates the group. Today however they are in a frenzy and all of the other danio's are frantically chasing the big one. It is getting to the point where I am worried that they are going to strss her to death. Has anyone else seen this behavior? Could it be a mating thing? Should I allow them to continue or should I try to quarantine her?