fish chasing other fish

Question
Why is one of my fish chasing the others all over the tank. The only time he stops is when they are all in one corner of the tank. Also that fish is nipping at the other fishes fins now they are all cut up. Why is he doing that and will it grow back?

Answer
Clara,

I would love to help you out but I do not know what kind of fish is doing the chasing and what kind of fish are the ones being chased? Without this information it is a bit hard to say. Some fish are very aggressive and some fish should not be put in the same tank with other types of fish. Let me know what oyu have in the tank so that I can better help you.