Most cats will be happier and thrive with the companionship of another. Two cats with no previous connection will become close friends… eventually.
Before You Bring The Cat Home
Be sure that the cat has seen a vet and been tested for worms and diseases like FIV that could be spread to your existing cat.
Make sure that now is the right time. This is going to be very stressful for both cats, so if there’s anything else on the schedule that might create more chaos over the first few days (a party, house guests, home renovations or repairs, a new baby on the way) this might not be the right time.
Prepare a private space for the cat for a short time. A bedroom would is always ideal, but be sure not to pick the room that contains your older cat’s favorite spot.
Place the cat in a quiet room with a door where you can put food, water and a litter box for as long as the feline wants to be there.
How long will depend completely on the personality of the cat. Some are adventurous and outgoing and may not want to be confined at all, anxious to check out the rest of their new environment. Others might want a full day alone under the bed or in a hiding spot.
When You Bring The Cat Home
Bring the cat directly into the quiet room. Spend some time with it and get to know each other, but leave periodically so the cat can explore on its own and start to feel at home and comfortable. If the cat hides under furniture immediately, don’t push it. Be warm and encouraging, but don’t force them out.
Your existing cat will know the other is there by scent, and will probably spend some time hanging out on the other side of the door trying to determine what’s going on. Your new cat will probably do the same. If the reaction of either cat seems hostile, that’s okay. They’ll come around. You may hear hissing for several days or weeks, but that’s normal. The cats will eventually come around.
When to open the door should depend on your existing cat’s behavior. When you feel the new cat is ready, open the door and let them check each other out from a distance at first. Stay close, in case you need to intervene. The chances of them getting along well immediately are pretty slim, so don’t be surprised when they seem to react to each other in an impolite manner.
You can help them along by making sure that neither of them feels needlessly threatened by the other. Give them their own feed dishes, and make sure there are plenty of toys to go around.
Make sure to give your older cat plenty of extra attention during the first days of the new kitten’s arrival. The old guy needs to know that he is no less important than before, and that life’s not going to change for the worse.