So, as you can see these guys used to be huge homies. They loved each other and would play and groom each other, i’ve had them both for about a year Orange guy (Willy) was mine for a year prior to adopting grey guy (Shoelace).
What happened - a stray cat visited our window. My unit is a basement unit, so my windows are garden level. This past Saturday, we had a tuxedo visitor at the window. Shoe did NOT like him at all, and tried attacking him through the window. Will, jumped up to jump the stranger with Shoe. Then BOOM both my sons are going at it, full screaming and hair flying everywhere. I let them duke it out for a little then separated them. A couple hours later both guys are chill, ears and tails are up as well as purring. I let them eat dinner on opposite ends of my bedroom door, and the begin playing under the door, pawing at each other with no signs of aggression. I let them chill out again, no signs of any issues. And Shoe start growling and they go at it again. No injuries besides will has a tiny scab on his paw.
I attempted to slowly introduce them again, this time over the span of 2 days. Meals at the door, pawing under the door, swapping items and spaces for scent purposes. Both cats were normal, and the window is off limits. I let them roam together for a supervised visit, all was well. Ended that on good note and they spent the night in separate rooms. Next morning they eat breakfast, and I let them be. BOOM besties again.
Now yesterday, I’m playing video games while they sit in front of me. Shoe on the ottoman, Will on the ground, and all of a sudden they go at it again. No reason really. I’ll add the when the scrap Shoe pees a bit. He peed on a blanket that i threw away, and I cleaned all other areas he pee’d on religiously.
I ordered a Feliway diffuser as well as giving them calming treats every day to keep them less anxious. Both cats when alone are their sweet selves, just seems to be different when they’re together. Any tips and tricks would help me a lot. I don’t want to rehome Shoe, as he’s the main aggressor in all the fights. I love them both so this is devastating to be completely honest.
P.S. the photos of them on their backs, they’re on the same couch maybe 5 inches away from each other. This was a day before the evil tuxedo visit.
Edit: Both Male. Willy is 3, Shoe is 2. Both fixed, shoe wasn’t fixed when they met. When they first met, Will would be the one to hiss or get mad. Shoe never exhibited any sort of aggressive behavior EVER.
TLDR: Cats saw a stray and fought. Inconsistent results when separating them. Tips and tricks pls!