How do I get my cat to like my other cats?

I currently have 3 cats (2,3, and 4 year's old) and I Just got a new one today (between 3-6 years old) The new one hisses and has tried to fight with them. How do I get them to like them? I've tried putting them in the same room and it hasn't work. Should I just wait for time to pass? Also I have a dog he hisses at.

just leave them both in the house and they will just be territorial...

The new cat is trying to find where it belongs. They're just establishing their hierarchy, once they figure out who's number one, two, three, and four things will settle down.

give them a couple of days.. and they should be fine

He's right. You'll have a lot of cat fights, but once they determine who the top cat is and so on they'll co-exist. They may still fight sometimes, just to challenge each other, but typically they will settle down in a few weeks.

just leave them 2 work it out for themselves, it sounds like the new cat could be trying 2 be the dominant cat but the others will soon put it in its correct 'pecking' order. try not 2 worry 2 much

Imagine the world from your cat's viewpoint. Here he is thrust into this new home with all these strangers. If it were you, I'm sure you'd have some problems coping and adjusting. If you were put in a new home all of a sudden with 4 new people and told to "just get along" you'd still have to go through the work of figuring all these new people out. Some you might like a lot, some you might never get along with. They might leave the toothpaste cap off, eat with their hands, never put the mayonaise away, you name it!He's just going to have to work it out with them. One day isn't enough time for them to get to know each other.

Well of coruse they will not get along because the old cats see a new animal hanging in their territory. So just give them some time and bound with all of them together and you should be fine.

You cant force them

You could try introducing them to the new cat one at a time, then it probably would'nt feel so threatned, and by the time you introduce the new cat it will already be familar with the other cat. And when the next cat you put with the new cat sees the other cat thats used to it is cool about it he/she probably will too.I did this with my dogs, i went for the calmer of the two first then when they were used to each other introduced the other.

when i got a new cat to introduce to my old cats, i had to do it very slowly. i kept the kitten in my room with food, water and litter, and let him out with the new cats a few times a day then put him back in my room. it does take a couple of days but they get used to eachother but i would just do it slow.

Get & label a bunch of clean rags from the $1 Store, et.al.Label each one per pet's name. Rub each pet per cloth. The new pet is rubbed w/ 4 rags. The new dog smells the other cloths (leave them w/ the new cat) and each of the other pets smell the new dog's cloths (leave 'em w/ the other pets). Give it time. E-mail thepetshow.com.