I have 2 male (brothers) Persian cats who are 4 years old. They are indoor cats how have access to a garden but cant not come into contact with other cats. In the past week they have been fighting so bad that we now cants keep them in the same room. They have never been like this before just the usual play fighting but now they are hissing and spitting at each other and the noise they make is horrible. they have been neutered and are both in perfect health. Please help.
it's never easy to diagnose these sorts of problems easily as there can be many causes. Territory, hierarchy or what i call trauma aggression are all possible causes. With the first two causes it usually starts out of the blue when one cat decides that he wants to be top cat and that where the cats live is his. Unfortunately all you can do in these cases is to make sure the cats do have their own separate places they can all their own including separate litter trays. Hopefully they will settle their differences in time and things will settle down.
Trauma aggression is really strange. This is when one cat is frightened by something, it could be a loud noise, being stepped on by accident or a trip to the vets. But for what ever reason and we might not even be too sure what the initial cause was, the cat associates the event with the other cat. Even if the other cat was not even around at the time, it's almost as if they want someone to blame. Anyway because they associate the trauma with the other cat they then become afraid of the other cat and behave aggressively. In this situation the only solution is to re introduce your cats again as if they had never met before See my page on introducing cats below. This is a slow process but is necessary to built the trust and confidence of the cats again.
I hope this has helped a little, but their is never a quick solution for this type of aggressive behavior.