[hawaiian mage]

Fish don't have sex... the female lays unfertilized eggs and then the male wanks off over them. Then is some casses one of the fish takes the eggs and stores them inside of themselves.

But the point remains that what you are watching is not animal sex, like you've come to expect from watching other animals, but animal masticating, like you've always assumed at first glance until the zoo keeper said otherwise.

I would probably seperate them... especially if they are expensive tropical fish.