I got a new cat about a month ago that was larger, and slightly older than my 10 month old kitten. At first, I had them separated by a screen between two rooms, then I brought them out together into the same room. Initially, they fought quite a bit and the fur would fly every time they did. To end the fights, I would just pick up one of the cats, or press both into the floor with the palm of my hand (not as cruel as it sounds). I'd punish the older cat with time in the bathroom, then take him out again later. They'd go into a stare-off again, then resume fighting.

It's been a month now, and my 10 month old cat (both cats are male by the way) is leaving the older one alone, while the older one continually charges him. My younger cat, who used to have the house all to himself can't go anywhere without the other one following him now. The younger one used to be playful, but now he looks depressed whenever the big guy is out of the room. He won't headbutt me, or rub against my leg anymore. He'll usually sit next to the walls or corners of the room waiting for the bully to charge at him again, or retreat to his litter box and have diarrhea. Will my younger cat lose the personality that made him so great? Will they ever get along, or will the older cat continue to push him around?