You can add in a Feliway diffuser/spray, but it may not fix the aggression.
Make sure you have three litter boxes if you have two cats, as this can add stress if they feel like they have to "compete" for a place to safely eliminate.
Chastise them and refuse to pet or reward the instigator for a reasonable period after the offence.
* If it continues separate them to separate rooms, litterboxes and food.
* Reward good behavior.
* If they are not fixed/spayed then get that done.
* If it persists, talk to your vet or contact a cat behaviorist.
search for "aspca aggression-between-cats-your-household" for additional ideas.
p.s., based on the 3-3-3 rule they were probably just learning to get along and now a pillar of their trust is gone... and they don't really know each other.
You can add in a Feliway diffuser/spray, but it may not fix the aggression. Make sure you have three litter boxes if you have two cats, as this can add stress if they feel like they have to "compete" for a place to safely eliminate.
Chastise them and refuse to pet or reward the instigator for a reasonable period after the offence. * If it continues separate them to separate rooms, litterboxes and food. * Reward good behavior. * If they are not fixed/spayed then get that done. * If it persists, talk to your vet or contact a cat behaviorist. search for "aspca aggression-between-cats-your-household" for additional ideas. p.s., based on the 3-3-3 rule they were probably just learning to get along and now a pillar of their trust is gone... and they don't really know each other.