Fresh shrimp, mussles, clams, scallops are all possible foods (anything fresh and marine - not fresh water - has potential). The most accepted has been the shrimp. You can try live crab and freeze it raw but the crab meat in a can (as well as most canned fish) has been cooked and recommendations are that it should be avoided (unfortunately, I do not know why).
Ok thanks, i would like feed my octopus live crabs as treats and frozen foods as a staple diet because i cant find feeder crabs. But i do find them at the pet store for $2.00 each. Maybe i can find a LFS that has them though.