I have a 55gl tank and with 6 fish adding to about 10in of fish. One of which is a yellow headed sleeper goby i have had him for about 2 months the tank looks grate but my sleeper goby dose not look good he looks as if he is starving he has lost a lot of weight. Is there any thing that i can buy to feed him? He dose not try to eat any of the flakes or brine shrimp that i feed the other fish. Please Help i feel that i might loose him or her.