Emerald Crab

Mythrax sculptus


(0 Reviews)

Emerald Crab

Emerald Crab

Mythrax sculptus


(0 Reviews)

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Care Facts

Care Level: Easy
Temperament: Peaceful
Diet: Omnivore
Reef Safe: Yes
Minimum Tank Size: 15 Gallons
Max Size: 2 inches

The Emerald Crab, Mithrax sculptus, are one of the most popular marine crab species for the home aquarium. They thrive in tanks with plenty of live rock and a sandy substrate as the like to graze searching for algae. As voracious algae-eaters, they can be incredibly beneficial members of a cleanup crew. If there is not enough algae or seaweed, they can be supplementally fed with prepared meaty foods. They should, however, be fed regularly to keep them from becoming aggressive towards their tank mates. Emerald Crabs are particularly effective against bubble algae. There is a reason emerald crabs are so popular; they are very easy to care for, require almost no attention, and are effective in in controlling pesky algal blooms hence keeping the tank clean. 


The Emerald Crab: A Molting Feeding Friend for Saltwater Aquariums

The Emerald Crab (Mithrax sculptus) is a delightful and eye-catching addition to saltwater aquariums. With its striking emerald-green color and unique characteristics, this crab has become a sought-after choice among marine aquarists. Let's explore the Emerald Crab's habitat, reef-safe nature, size, lifespan, diet, aquaculture potential, molting process, other common names, and compatible tank mates.

Habitat of the Emerald Crab

The Emerald Crab is native to the warm waters of the Western Atlantic Ocean, ranging from the coast of Florida to the Caribbean and Gulf of Mexico. In the wild, they inhabit rocky shores, coral reefs, and intertidal zones.

Reef Safe and Algae Control

The Emerald Crab is generally reef-safe and poses no threat to corals or other invertebrates. On the contrary, they benefit reef aquariums as they help control unwanted algae growth.

Size and Lifespan

Emerald Crabs are relatively small, typically growing up to 1.5 to 2 inches (3.8 to 5 cm) in carapace width. They can live for two to three years in a well-maintained aquarium with proper care.

Diet and Algae Eating Abilities

In their natural habitat, Emerald Crabs are omnivores, feeding on algae, detritus, and small invertebrates. In a home aquarium, they are excellent algae eaters, helping to keep the tank clean and free from excessive algae growth.

Aquaculture and Sustainability

The Emerald Crab is available in the aquarium trade, and captive-bred specimens are also accessible. Breeding and propagating this crab in captivity have been successful, making it a sustainable and eco-friendly choice for marine aquariums.

Molting Process

Like other crustaceans, Emerald Crabs undergo molting, a process where they shed their exoskeleton to grow larger. The crab is vulnerable to predation and stress during molting, so providing ample hiding spots and a secure environment is crucial.

Other Common Names

In addition to the name "Emerald Crab" or "Green Emerald Crab," this species is also known as the "Green Clinging Crab."

Compatible Tank Mates

Peaceful snail species like Astrea snails or Trochus snails can coexist with the Emerald Crab. Snails contribute to algae control, complementing the crab's role as an algae eater.

Some species of hermit crabs can be suitable tank mates for the Emerald Crab, provided they have sufficient shells to inhabit.

Peaceful blennies are also compatible tank mates. Blennies come in various colors and patterns, adding character to the tank.

Peaceful gobies can cohabit harmoniously with the Emerald Crab. Their small size and diverse range of colors make them great additions to the aquarium.

The peaceful Cleaner Shrimp (Lysmata amboinensis) can be compatible tank mates. They provide an interesting dynamic with their symbiotic cleaning behavior.

In conclusion, the Emerald Crab (Mithrax sculptus) is an enchanting and valuable addition to saltwater aquariums. Its striking appearance and algae-eating abilities make it an excellent choice for reef aquariums seeking a natural and effective algae control solution. Aquarists can enjoy the charm and practicality of these emerald-green gems in their aquatic havens by providing them with a suitable environment and compatible tank mates.


Reviewed by: Tracy Hedine on Jan. 2, 2024


Reviewed by: Micah Clark on Dec. 18, 2023

As advertised ????


Reviewed by: John Stone on Dec. 10, 2023


Reviewed by: Edward A Wilburn on Dec. 10, 2023


Reviewed by: Steven Bauer on Dec. 6, 2023

Very active


Reviewed by: Alvin Barbes on Dec. 4, 2023


Reviewed by: Andrew Hayes on Dec. 3, 2023

Very active going to town on algae clean up instantly


Reviewed by: Mary Fetterley on Dec. 3, 2023

Very active and alive


Reviewed by: Tony Goszulak on Nov. 8, 2023


Reviewed by: Michelle Kuhn on Oct. 29, 2023


Reviewed by: Anthony Papp on Oct. 23, 2023


Reviewed by: Jerry Duvinsky on Oct. 2, 2023

As always they do their thing


Reviewed by: Alvin Barbes on Sept. 24, 2023


Reviewed by: Fishes261@@@@ Rose on Sept. 22, 2023

I got this guy 7 days ago. He was super cool. I saw him the first day and haven’t saw him since.


Reviewed by: Lisa Davis on July 8, 2023


Reviewed by: Tim Corrie on July 3, 2023

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