Are you sure it isn't a "key-hole cichlid"?
sorry!
I am a bit suspicious that it is a disease since diseases take a while to chew through tissue, usually damage is the culprit if the injury suddenly appeared. Can you post a picture? Do you have a puffer fish in the tank?
I am a bit suspicious that it is a disease since diseases take a while to chew through tissue, usually damage is the culprit if the injury suddenly appeared. Can you post a picture? Do you have a puffer fish in the tank?