Thanks for all the support and ideas.

We've tried feliway and all the herbal remedies I could get my paws on, to no success.

To calm him I spray a breakaway collar with feliway and put it on him. I'm not sure if it's the collar or the spray but this generally helps for a bit. But it failed us on Friday night too.

I gave him his usual prozac plus half yesterday after the vet and he seems much calmer this morning.

Candace, he's a perfectly healthy kitty, save for his anxiety/aggression.

I have to wonder if he needs to be the "only" kitty now, after the fire. Which is sad because he and Cali used to love each other so much.