The Emerald Mithrax Crab is a commonly kept crustacean and is widely known for its ability to help control outbreaks of bubble algae in reef aquariums. These crabs are, however, omnivorous and will not hesitate to help clean up any excess or leftover meaty foods or waste that can settle on or in various surfaces of the tank. Emerald Crabs tend to stay hidden away during the day, emerging from small crevices or ledges to hunt and scavenge for algae and other debris at night. Although generally peaceful, in the absence of sufficient food, Emerald Crabs may demonstrate opportunistic behavior and attempt to predate on smaller invertebrates, fishes, and sometimes corals, so it is imperative to keep them well fed in established systems.