Crustaceans are a group of aquatic animals that have a hard exoskeleton and jointed appendages. They include prawns (5 letters), decapods (7 letters), SHRIMP (6 letters), CRAYFISH (8 letters), lobsters (7 letters), crabs (4 letters), isopods (6 letters), krill (5 letters) and shells (5 letters). These animals can be found in both saltwater and freshwater habitats, and they play an important role in the food chain.