I have a 10 year old cat (pic) that has lived with other cats

Unfortunately anon the best thing will be to just wait. Cats behave like this many times but then they realize that the newcomer isn't a threat and become friends with him.
I have two cats now and my older one behaved like this when we got the other yet now he can't live without him. Whenever the other runs away he's nervous til he comes back and even if the other steals his food he doesn't do anything to him and even purrs sometimes.
When he'll get used I assure you he's gonna love him.

>>2029558
Thanks anon, ill try to keep a business as usual approach, keep feeding them together as much as I can and establish special places for each cat

Cats aren't dogs. A new kitten is isn't gonna "liven up ol' Bessie." It's just annoying when the last thing your old cat wants to do is play or deal with a rambunctous little brat. Let the old thing live the rest of its life in peace and then get a new kitten.

>>2029618
I'm in a position similar to ops, and this is the conclusion I've reached.

Not really related to the thread
but my cat is super aggressive to other cats in fact she's a murder. she's an indoor cat but will time my arrival from work and wait for me at the door ready to escape the moment I enter. 80% of the time she'll just lay there on the porch doing nothing until I get her to go back inside, but every now and then she'll spot a stray cat and run as fast as her legs will carry her then she'll try and tear it's throat out. so far she's never lost a fight but I'm afraid she'll get herself killed one day

how do I get her to be less of a psychotic murder?

>>2031945
She's very territorial. She doesn't like seeing other cats up in her shit . You might try letting her out on a leash so she can leave her scent and rub up against some bushes so other cats know she ain't fuckin wit no other niggas .

I'm actually in kind of the reverse situation from OP. I got a new kitten to be the buddy for my relatively young cat (2 years), although the kitten was also a rescue so there were many issues related with that. Ultimately, she (big cat) got used to him (little cat) and they started to act like buddies, i.e. they'll play (it's definitely play, not fighting) which big cat loves, they'll nose-boop, they'll groom each other, cuddle and nap together, and there is no food aggression whatsoever. My kitten will practically sit on top of her and silently watch her eat and they are perfectly fine with this (part of this is that he loves big cat food way more than kitten food, so he's a tad jealous perhaps).

All that said, my kitten is still a huge fucking shit sometimes. I got him at five weeks (way too young, but he was going to be shot by farmers otherwise), and he had to be quarantined for a fairly long time because of ringworm. So I understand that he's not the most stable, but I just don't understand his behavior sometimes: He'll be grooming big cat, and suddenly he'll decide to just bite the shit out of her, which makes her hiss and growl and all that. And it's like her face, the back of her neck, and sometimes her feet (he's a huge shit). What kind of training and stuff do I have to do to make him behave nicely?

He is 7 months now, got him fixed at 6 months and it still continued after that. I don't think he's teething anymore, and he doesn't have many issues with biting my hands and such anymore (I tried to train him out of this best I could). Any suggestions?

>>2031945
Is she fixed?