Brought A New 5 Months Kitten To My 4 Months Kitten

[10009891]

Last night I brought a new kitten and they were calm about each other, but now this morning they're hissing and physically fighting. I am concern they'll harm each other. At the start they were fine but don't know what's the fight now. Should I worry?

 

[talkingpeanut]

You need to separate them completely and do a slow introduction. Keep them in separate rooms, feed them on opposite sides of a door. You can’t just throw cats together and hope for the best.

Are they both spayed/neutered?

 

[LTS3]

Read this for tips on how to introduce cats: How To Successfully Introduce Cats: The Ultimate Guide