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?
You're slightly overstocked IMO with the RTC and Oscar but doable if you had the right temperaments. This is where your specific problem lies. Looks like you need another tank or you have to sell one of them/give it away.