Why's my cat being agressive

[kimmore]

My male cat (1yo and neutered) is acting angry with my female cat (9 months and neutered).
He wasn't like that with her before, he would play with her and stay next to her, but after getting neutered he started avoiding her and sometimes when he sees her next to him he would hiss at her and tries to attack her (not always, i think it's mostly when she gets super close to him or tries to lick him) and when he's sleeping with me and she tries to join us he gets mad.
I really don't know what's wrong with him, she was 2 months when I adopted her and he was 8 months (he was still in heat). I feel bad for her because she gets scared whenever she passes by him.

 

[di and bob]

When was he neutered? Sometimes they just don't feel well for a while and keep all other cats at bay. Hormones stay in the system for at least 30 more days post-neuter. The anesthesia can make them 'different' forIf it had a while, and the trauma he has gone through will stay for a while too. I think it will blow over in a few weeks, he just needs time to heal physically and mentally, it could take a month or two.

 

[kimmore]

When was he neutered? Sometimes they just don't feel well for a while and keep all other cats at bay. Hormones stay in the system for at least 30 more days post-neuter. The anesthesia can make them 'different' forIf it had a while, and the trauma he has gone through will stay for a while too. I think it will blow over in a few weeks, he just needs time to heal physically and mentally, it could take a month or two.

He did it on the 9th of January 2023, he also got sick after the surgery and had to get several shots and mediations, so I guess just like you said he's behavior changed because of the trauma, hopefully he'll get back to normal. Thank you so much for your reply

 

[ArtNJ]

He should be feeling ok a month after the surgery. So I'm not sure we know exactly what is going on. Regardless, give them a little break. Sometimes a few hours is enough, but maybe a day or so of separation to start if this has been going on for a bit. Sometimes that isn't enough, but its a place to start.

 

[danteshuman]

I would separate them and reintroduce them. Sometimes cats smell weird after the vet. So site swapping for a couple of weeks should hopefully do it.