The Emerald Crab is known as Mithrax sculptus in the scientific realm, but is also frequently referred to as the Green Crab or Green Coral Crab by laymen. These relatively small saltwater invertebrates prefer the saltwater environment. Many people add these crabs to their saltwater tanks to assist with cleaning and algae reduction. Below you will find a complete examination of the Emerald Crab, specifically when they are kept in household aquariums.