Cats, like many animals, are territorial, and randomly throwing a second cat into your house is just asking for trouble. You need to indroduce a new cat slowly if you don’t want any conflict. The easiest way to solve a problem is to prevent it from happening in the first place.

Before you even bring your new cat home, get it checked at the vet and make sure that it doesn’t have any diseases your other cat may be able to catch. Also, when choosing a cat, keep in mind that two males will not get along as well as other gender combinations.

As soon as you walk in the door, take the carrier to an isolation room where the new cat will not be able to come in contact with your other cat. A spare bedroom or a bathroom will work. Try to make sure your existing cat (Cat A) does not see the new cat (Cat B) along the way. Also make sure to choose and cat-proof the isolation room BEFORE you get the new cat. Let it out of its cage and leave it on it’s own to explore its new surroundings. It needs to adjust to its change in environment before it can adjust to you or Cat A. Take the cat carrier with you and place it somewhere Cat A has access to. Different cats will have different responses to the cage. The entire first step is to let Cat A get used to Cat B’s scent. Make sure to keep the cage out until Cat A loses interest in it, and don’t interrupt it while it is investigating.

After a few hours, visit Cat B. Bring it some food. If it lets you, pet it and interact with it. If it doesn’t, don’t force it. Stay in the room with it for about half an hour, and if it doesn’t want you to touch it, at least talk or read to it. Make sure to visit it several times a day. You may notice Cat A begin to act slightly hostile around you; this is to be expected. You’ll smell like an intruder from spending time with Cat B, and Cat A might be confused. Treat it as you normally would. Wait until all hostile reactions towards you and the door stop before moving on to the next step.

After all negative reactions to the new scent have ceased, open the door a crack. Don’t make it big enough for their head to get through, or they can get their whole body through. Make sure to block the door with a door stopper or something heavy on both sides so that niether cat can open the door any farther, even if one were to aggressively throw itself against it. There’s most likely going to be a negative reaction when they first meet, so don’t be worried if the two start trying to whack each other through the door. Wait a few days for hostile reactions to slow to a minimum before moving on to the final step.

When Cat A isn’t around, open the door. Let Cat B explore on its own and come across Cat A by itself. Don’t bring one cat to the other. Skirmishes are likely to happen, but don’t break them up. The cats must resolve the issue themselves. However, if you think one of them has seriously gotten injured, throw a blanket or large towel over them to stop the fight and get the wounds tended to immediately. Never reach into a cat fight and try to pick one of the combatants up.

At first, keep Cat B’s food bowl and litter box in the isolation room. Wait a few days, or even a few weeks, until the cats develop a friendship, or at least a truce, before moving them together. The amount of time it takes for your cats to adjust to each other will vary, but younger cats tend to get along a lot better than older cats. Hopefully, with time, your cats will become the best of friends.