Well, even though their diet mainly consists of crustaceans a single item usually cannot meet the nutritional standards which is why a variety is best. Shrimp (shell on), crab (blue crab is common), fish (capelin, silversides, herring, etc.), squid, and even live crayfish or fiddler crabs (defensive claws removed) for enrichment purposes. They only need to be fed twice/weekly and only what they can eat; Once they become lethargic about taking the next bite, stop feeding immediately. Morays have been known to stop feeding for up to 6 months. Most predators should also have each meal enriched with some type of Thiamin-E based additive.