bad cat behavior

Question
My cat has turned aggressive since I moved and got another male cat.  He just recently started fighting with the male cat and also brutally attacked my fiance.  I don't know what to do, can you help?

Answer
I am assuming, here, that both cats are neutered.  If not, have this done immediately.  That should help.

I'm not sure what I would do in such a severe case.  You should separate the cats for now.  Try feeding them on opposite sides of a closed door so that they start to associate this positive experience with each other.

However, because he's redirecting his aggression toward your fiance, I think it would be best to consult a vet or animal behaviorist.  There may be specific exercises you should do with him.  Even a couple days on a mild sedative or a course of antidepressants may be recommended.  Could be he just needs a little help to relax before he is able to start adjusting to the changes.