Cat beats up other cat

We have four cats. Sergio is a huge black boy, terrified of men, scared of most other people. Belladonna is a sweet, quiet, delicate, sweet himalayan princess. For some strange reason, Sergio has started chasing Bella and ripping out her fur. So Bella hides alot. All our cats are neutered asap. Please someone help us. Poor Bella has terrible knots all over from Sergio's bad behavior.

I would have a thorough exam done on him. Sometimes a cats change in behavior might mean something internal is wrong.

If everything checks out ok, then separarte them and reintroduce them slowly. Do they go outside? Has there been other stray cats hanging around the house? These things can trigger aggressivness in indoor cats.

I have this same proble with 2 of mine. All 4 are fixed. Levi is a sweet gentle guy & is at the bottom of the pack. Isaac is 2nd in command. Jordan is top kitty & likes to mount Isaac to remind him who's boss. Isaac just puts up with Jordan. So Isaac tries to do the same to Levi, only Levi won't let him. When Isaac gets ahold of Levi, Levi pulls away causing his fur to be ripped out. In my house it is a dominance issue. It tends to come and go. Levi spends a lot of time just avoiding Isaac, but I also found that a Feliway plug in helps reduce the occurance.

I would have a thorough exam done on her, too. Cats can detect when other cats are ill, even though there aren't necessarily any outward signs to alert us. In the animal world, a sick animal is a weakened animal --- and weakened animals are targets of attacks. I'm not saying that's what's going on here, but it's enough of a possibility where a vet visit is warranted.

i have to ask, what are all those emoticons on the side and below everyone's posts?

Let's see. In the header to the left is my Avatar, that is my last cat Smokey's photo. To the right of my name are links to the pages of my 4 cats. The cute little things all the way to the right are gifts that we have given each other. At the bottom of our posts are our signatures. There are various rules designating when you can make changes & additions to these things based on length of memebership & number of posts. There is a forum where you can ask all kinds of questions, but I forget the name right now. Maybe someone will be along shortly who can answer all your questions.

I have lived with very many cats over decades and one thing that never changes is males going after females, sometimes in a very serious way (all neutered). The only answer I personally have found is to keep them separate when you're not around, to help the female to have safe places (high up small ones that only one cat can access at a time), and to monitor carefully when you are around. It's maddening, but seems to be a fact of cat life and I also think it's a dominance thing. In the end, cats are 'animals', and barely domestic at that, let alone never really 'tame'!