Resident cats fighting each other when introduced new cat to household

Help!

We adopted a new 9 week old female kitten and brought her home yesterday.

We already have two 1 year old female sister cats who have always gotten along like best friends. We let our old cats meet the new cat once but since then have kept the new cat separated in her own room.

But since the meeting, our two sister resident cats won't go near each other, and each time they do they hiss and growl at each other and have even started fighting.

Is this normal? What can I do to help tame the situation?

Please, any help or advice would be appreciated. I'm worried about the relationship of my two cats.

This will happen. Their peaceful living arrangements have been disrupted. You can sprinkle a little pure vanilla extract on all of them so they smell alike. Try Feliway too to calm them down a bit.

Give it time. Keep them seperated at least until your new kitty can go to the vet and be tested and make sure she is healthy and everything. Is everyone spayed? That will make a big difference too. Females are always so dramatic. It is a lot easier to have males get along IMO. Females get so PMS-y

Depending on your cats personalities it could take anywhere from 2 weeks to 2 months for your kitties to get a long. They will probably all be upset with eachother because a new hiearchy needs to be made. Don't you worry one bit, after some time and a lot of hissing and growling your kitties will get along. It's especially easier bringing a young kitty into the picture because it's just a baby and adult cats seem to realize that.

Thanks, we went out and bought Feliway today and already it seems to have calmed them down a bit. Our resident cats haven't been hissing at each other so much today, although last night one of them denied the other access to our bedroom.

It's hard to be patient but I know that it'll just take time. Thanks for your quick response and help I'll post any progress.