So you know that Diego was attacking Cali and that Diego is on prozac. Well sometimes he still goes after her. This is when I break out the feliway and a collar for each of them. I spray the feliway on the collar and each kitty gets to wear one for as long as I determine is necessary. All chasing, biting, etc. stops immediately. I've been doing this for a while. Now, when they misbehave all I have to do is pull the collars out and shake them so kitties see them and all action stops immediately. They do not want to wear the collars so they settle right down.