I have a 7 yo MN cat for the past 7 years that has always been an only cat but does travel with me frequently to visit relatives and gets along with their 3 cats. Recently adopted a now 7 months old kitten 2 months ago. He was neutered last week after he started attacking the older cat.
So the older cat (OC) has always slept with me, sleeps in the window, stays off the counters, etc. Basically, he’s perfect. The new kitten (NK) was absolutely fine until last week. I introduced them slowly over a couple of weeks by leaving NK in one room, then started alternating and fed them by the door. Everything seemed to be going fine until NK decided he should start keeping OC out of my bedroom, away from the litter box, scratching post, etc. I came home one day last week and OC had hair everywhere that NK had ripped out in chunks. NK will mostly ignore OC but then gets this crazed look in his eye and chases him until he jumps on top of him and much hissing, growling and flying fur ensues.
I’ve started breaking them up and giving NK a “time out” of 3-5 minutes in a crate or separate room. Is this behavior normal? Will he settle down after a few weeks post neutering? I have a feliway diffuser, and lots of toys.