Friendly cat gone bad!?
Well, there are three cats in my parents house at the moment. Two visitors, Moria (1 year) and Rum (3 years), and one resident cat, Oliver (5 years).
Rum is my sister's cat and he stays over every now and then. He and Oliver get along OK and up to now, Rum was a happy go lucky cat that loved everyone and wasn't aggressive at all.
Moria's new, I brought her to my parents house for the first time 3 weeks ago.
Now, Oliver is ok with everything: he loves being outside and there he's the king. Everyone respects him.
But the two visitor cats are having problems lately. At first Rum tried to play with Moria but she was frightened (he's really big compared to her) and lately Rum has changed his friendly mood into total aggression. He hisses at her constantly and runs behind her trying to hit her, corners her and would probably do some big damage if I didn't stop him.
I wonder why the change of attitude? They both are "inside the house cats" and Moria loves eating Rum's food (I try to avoid it, though). Also, Rum is used to lots of attention and now he doesn't have as much.
Anyway, any suggestions on how I can make Rum less aggressive and back to his friendly self?