I have one apollo shark, he is very aggressive towards my other fish. He's chases them and nips their fins. I know your supposed to have at least 4 for them to school with. Im wondering if this is why hes being aggressive. I want to buy more but will have to wait till I go to the city this weekend. Will buying more fix this problem, or make it worse. All my fish hide all day because of him . They aren't supposed to be aggressive so its a little odd. I also don't want to get rid of him because I'm quite fond of him.