Blue lines are usually pretty mellow groupers. I have seen one though that beat the heck out of a blue jaw trigger. They are a hardy fish. They, like all groupers, will eat anything. Feed mixed meaty preperations like shrimp, squid, krill, silversides, etc. What size tank is he in? Bo
Thanks for the replies, the grouper is a 4" fish in a 80 gallon tank with a yellow tang, tomato clown and a baby banded cat shark. I am planning to upgrade my tank within a year to a 200 gallon. This guy is definitely cool, very curious, you feel that they are watching your every move. The yellow tang who's been in the tank for four months actually bosses the grouper around. Of course like grouperhead said, he eats everything.