How crabs eat?

SAND CRABS EAT SEA CREATURES LIKE CLAMS,FISH AND PLANKTIN THEY ALSO EAT FUNGI,BACTERIA,ALGEA,SNAILS AND WORMS.ALSO SNAILFISH AND SNAILS AND PLANTS. THERE IS A LOT OF OTHER STUFF TOO.SO YOU CAN FEED CRABS SMALL FISH BUT NOT HUGE FISH.