Hi i have a 7" Blue Angel that i've had for 2 years. Just recently in has started to hide in the rocks constantly. Does not even come out to eat. It used to swim every where and was very active. I have not added anything to the tank or changed a thing. What i can see of the fish appears to be ok. I don't notice anything physically wrong with it. It has been acting this way for about a month. It is the largest fish in the tank and has always been the dominate fish. So i have no idea what is wrong. Any suggestions?