On Friday We got a new cat who is roughly 5 months old (female) however our 2 year old (female) didnt take a great liking to this. She hissed and growled and hid under the bed till saturday night, after that she seemed ok, but was extremely distant from myself. The New cat is in a seperate room from and they cant get access to eachother. I have let them see each other, by me holding one and someone else holding the other.. It went ok (the 2 year old just struggled to get down so she could hiss and run away into another room)

We had the 2 year old spayed yesterday.. She seems very crouchy.. Hissing, growling and hiding under the bed again. Im worried because internet research came back with after cats are spayed they tend to settle down right away. I understand shes just had an operation. Im just worried. I really want her to be friends with the new cat and actually be a nice cat to have around instead growling and hissing all the time.

Any advice would be great and past experiences of what happened and what you did would be great too thanks.