Marine crustaceans are a group of aquatic animals that live in the ocean and include prawns, SHRIMP, crabs, barnacles, turtles, blue crabs, and sand crabs. Prawns have five letters, SHRIMP have six letters, crabs have four letters, barnacles have eight letters, turtles have six letters, blue crabs have eight letters, and sand crabs have eight letters. These animals are typically found in shallow waters and can be used for food or other purposes.