Cats/new cat in the house
We have a 2 year old male, Stevie, who has been the sole kitty in the house since he was 12 weeks old. He's a total sweetheart and very docile/personable/curious. He never postures, etc. when he sees other cats outside (he checks them out thru the glass door).
We thought we would get him a buddy and recently brought home a year old female, Ali, just under a week ago.
She has been in her own room for just under a week with her own litter/food/toys and they have swatted at each other under the door.
I have also let each of them spend time roaming the house separately. I have put each of them in a carrier in the living room so that the other could check them out...
Ali does nothing but HISS, posture, and growl when she sees Stevie while Stevie at first, just stared at her and was more curious.
Today I had them about two feet away from each other and Stevie is beginning to get a little more schemey! He keeps trying to sneak up on her and has his ears back like he's going to pounce. In fact, she was following a laser light and he ran off after her, chasing her back into her room and under the bed. I ran in after and stopped him from going under the bed after her...
Should I allow them to just be together and fight it out? Or should I keep them separated longer? I don't want either to hurt the other...
you are doing all the right things unfortunately depending on the first seven weeks of any cats life where they have to be socialized with other animals, it can take some time. A cat that is used to other cats from a young age will except other cats fairly quickly however if not then they see each other as a threat to their territory and they will have to sort out whose boss in the house.
I would recommend that you continue with the carrier training for another week or so and then as you are doing short supervised meetings. But it may still require a little spat before they settle. Remember cats don';t like to get into serious fights as injury is not in their best interests sometimes fights can look worse than they are.
When they are together and if one looks like they are going to attack make a sharp loud noise like banging the floor or shaking noise maker tin. cats respond better to this sudden noise rather than our voices. Hopefully over time they will settle down together.