I have two cat who have lived peacefully together for 3 years. Since yesterday they have been fighting. I can't figure out why or who is starting it. I think it is the younger more dominate male cat (neutered) cat. The older female (spayed) has always be submissive. I have observed them together fine then he smells her and hisses at her which sets her off growling and hissing. A couple physical fights. Now today it seems she is instigating it growling the minute she sees him but it may be only because he has been picking at her.
I separated them over night and in the morning she was very upset he was locked up. Crying for me to open the door. But right away they started in on the fighting. So
So far today she has stayed hidden and he has staked out her hiding spot.
Only things I can think of is she is sick and he smells it or very small possibility that another cat sprayed her through the security door. They were at the door when this started. But I don't really think she would stay at the door if another cat came up. She is very skittish and submissive.
She has been using the box fine and eating fine. I've checked her over for sore spots and she doesn't respond. And it looks like so far no boo boos from the fights.