How can i make my old cat like my new kitten?
Your key statement is “just got”. Cats don’t like change, and bringing in four paws with fur is quite a change. Hissing and growling is to be expected, since your female now has a rival for alpha status. Since they are both kittens, it shouldn’t last too long. When she understands that hissing isn’t going to make your new kitten disappear, she will come to terms. Some might suggest separating them, with a slow introduction. But they already know about each other, and if hissing is the worst of what you are seeing, let them mingle and they will sort it out. Hopefully, your female is spayed, as she will soon become sexually mature. No, I am not worried that he will try to mate with her right away. It is just that a female cat in heat is not pleasant to be around. They may start to wrestle. Just remember, kittens play rough. Very rough. So a concerned pet “servant” can easy over-think what is happening.
Your six month old did not want company, let alone another cat. Get both altered ASAP. If they were my kittens, I would keep the 3 month old in a room of his own, with his own food and litter box. It would be where the female could smell him under the door and maybe start to play with him by poking a paw under the door. I would give the male time out in the rest of the place starting with 15-30 minutes at a time to see how it goes, while putting the female in his room. Then when they seem comfortable, allow them together for short, short periods. Hopefully they will want to be together before long. Keep them apart until the female is not upset by his presence. Cats can get really upset at an “intruder”. It can be hard to change that first impression. How does the young one act? Give the female a bit of catnip every few days (it only works every few days for a bit) or give her special food for not hissing at the boy (canned chicken?). I hope that you can find what will work so your kitt
