Instructions
Have your cat checked up by your veterinarian. Your cat might be pulling out the other cat's hair as a result of a serious illness. When a cat is sick, taking out miserable feelings on another cat is not uncommon.
Have the aggressive cat spayed or neutered if you haven't already done so. Cats that haven't been fixed often act aggressively toward other cats.
Reintroduce the cats. A cat introduction should be done very carefully, and it takes many days or weeks. Isolate the new cat to one room. Allow the cats to smell and play through the door. Take an item, such as a blanket, that has the new cat's scent from the room, and give it to the other cat, and vice versa. Switch their environments so they really get used to each other's smell. Then, reintroduce the cats.
Give your cats space. Territorial aggression can sometimes be fixed by giving your cats more perches, scratching posts and hiding places. Have multiple food bowls or feed the cats separately, and have a few dishes for water. You should provide as many litter boxes as you have cats. The less things there are to fight over, the less likely the cats are to fight.
Give your cats treats when they interact nicely rather than aggressively. This will teach them that calm behavior reaps tasty rewards.
How to Stop My Cat From Pulling Out Another Cat's Fur
Cat aggression is not something that you should take lightly. If one of the cats in your household is pulling out another cat's fur, then you probably have a cat aggression problem. This type of behavior can lead to serious injury even if your cat has been declawed. To deal with this issue, you will need to implement several training techniques. If you cannot fix the problem yourself, consult a professional animal behaviorist.