They are also sand-sifters. If you have nutrition in the sand, he will be getting that. If the tank is very new, that's a problem. Mine will try almost anything now, but when he was new he couldn't figure what to do with flake. He prefers pellets, the super-small Formula One sinking pellets. He'd like the worms, or brine shrimp, or maybe cyclopeeze, but that's a bit fine for him. He wants to get something he can chew on for a while: that's his normal mode of eating. The chromis shouldn't spook him if he could figure out how to eat the food. Mine is in with chromis and firefish, and holds his own right well.