Aggressive cat

I have two cats that I have had since they were old enough to leave there mother, they are about 3. One of them is very aggressive with all other cats except his brother. Last night he pretty much tried to kill my roommates cat. They are the same size but my roommates cat is now terrified to move from an area he feels safe. I have had problems with him being aggressive with other cats in the past but I never understood why. His brother is very docile and gets along well with my roommates cat. They are both extremely loving and friendly with people. If anything the aggressive one is more friendly with people. He will let me rub his belly and just lay there, whereas my docile cat will actually bite and use his claws but in a playful way.  I am at my wits end with him. Any time he sees my roommates cat he just lunges at him and pretty much wont stop viciously attacking him unless i intervene. I really need some advice!!

Oh, I'm sorry, that's so distressing.  Is your cat neutered?  Has he always been aggressive with your roommate's cat or is this new? 

Have you ever tried calming treats or collars on him?  

Here's an article that may be helpful, too:  http://www.thecatsite.com/a/breaking-up-cat-fights

Thank you for your input,

Ya he is fixed. I had problems with him with one of my other cats as well. My mom ended up just keeping my other cat because my aggressive cat would not stop attacking him either.

I had my own apartment for awhile so I didn't have to worry about him with other cats but when I moved in with a friend a little over a month ago the problem started back up almost instantly.

I am not aware of calming treats or what kind of collar may be useful in this situation.

I dont know what to do with him, It is really hard to keep them in separate parts of the house but even now my roommates cat is still scared to death to just walk around the house for fear of seeing him. I need all the advice I can get. At this point I will try anything

Thank you for your input,

Ya he is fixed. I had problems with him with one of my other cats as well. My mom ended up just keeping my other cat because my aggressive cat would not stop attacking him either.

I had my own apartment for awhile so I didn't have to worry about him with other cats but when I moved in with a friend a little over a month ago the problem started back up almost instantly.

I am not aware of calming treats or what kind of collar may be useful in this situation.

I dont know what to do with him, It is really hard to keep them in separate parts of the house but even now my roommates cat is still scared to death to just walk around the house for fear of seeing him. I need all the advice I can get. At this point I will try anything

Hi. Sorry to hear you are having problems with your cat not getting along with your roommate's cat. That must be a hard situation to deal with. You may have to try and keep them seperated. There are times when a cat will love humans but not necessarily other cats or animals. Some cats want to be the only cat in the household. He may be fine with his brother since you got them at the same time. I do wish you the best of luck with your cat. Take Care!!