I have a male red Texas cichlid and an Oscar together in a 75 gallon tank. There was only a problem when I forgot to feed and the red got hungry. He would nip at the Oscar but the Oscar did not fight back at all. I bought a green Texas female to put in the tank with them. Not even 12 hours into this the red had the green beat nearly to death. I separated the red into another tank by himself. Does anybody have any other recommendations on what to do about this?