If you are really worried then you should take him to the vet to check that all is good. Leave them separated, they obviously don't like each other, if you put them together again, you may end up with a dead bird.

I have two female birds and a male. My one bird has a feather missing near her wing bone. The other female is now attacking my male and he's bleeding!!!!! So we put him in another cage by himself. Now both females are doing good together. How can I save him??? Birdie CSI anyone?