He'll eventually need mysis too. And if you use a black mussell from the grocery store, preferrably live, he'll get all the vitamin A he needs as well. A diet of brine shrimp will not fatten him up - not enough protein or vitamins. Great fibre diet, but, thats about it. Split the mussell with a pocket knife, cut the little shell mussell in there and spread it wide open. Rinse in tap water for a second and lay it on the bottom of the tank. Leave it be for a while, he'll find it. Enjoy the show, all the fish like it. My maroons try to get in the way of the copperbands so they can have it all. Same with clams, but, yours is pretty small and the mussells shred up easier.