2 mature cats start fighting suddenly

Question
My problem started about 4 months ago. I used to live with my mother and we had 2 older male cats (we had more than 2...but these 2 in particular)that got along great. I moved out in July, and I brought 2 kittens, the father of the kittens and his friend, my other older cat. The 2 older cats are around 2 years to 2 and a half years old. When I lived with my mother, they got along so well, that it was agreed when I moved, I would have to take them both because they couldn't be separated. Since I have moved, the older cats have done nothing but fight. They growl, hiss, and attack each other to the point I think they are going to kill one another. They both get along with the kittens, but I don't understand why they got along so well before and not now. They are both neutered and both indoor cats, as are the kittens. The kittens are also male and both neutered if the information helps you. I hope you can give me suggestions on how to bring them back to being friends again.

Answer
Erin,

If, after 4 months they are not getting along, I am not sure they ever will.

Cats are very, very teritorial and, by changing abodes, all the rules have changed and each cat has to reestablish their place in the new environs.  Normally, kittens do not care, but adults can be as if they no onger know each other in ther new place.

Also, in the new place, the rules of their games have probably changed.  It is possible you are misinterpreting rough play and noise for fighting!  Cats will play with each other very, very roughly and appear to be fighting.  Has anybody really been hurt or blood drawn?  Loose fur does not count! It is not really clear to me that they are not getting along as they may be getting along in different ways than you are used to.

You may want to reevaluate what is really going on between these two.

Best regards... Norm.