I have one small sixline wrasse that hides behind (dead) coral all day. He lays there so much we've named him Flounder. I have other fish in the tank, but all are peaceful and do not pick on him or each other. (2 clowns, 1 yellow tang, 1 coral beauty, 1 blue damsel, 1 strawberry gramma and 2 bi-colored damsels). Can anyone tell me why he hides all day?