Common name: polkadotted hermit

General information

The Emerald Crab, scientifically known as Phimochirus operculatus, is a popular marine invertebrate in the reefkeeping hobby. These crabs are known for their vibrant green coloration and their beneficial role in the aquarium as algae eaters. They are particularly adept at controlling bubble algae, which can be a nuisance in reef tanks.

Emerald Crabs are nocturnal and tend to be more active at night. During the day, they often hide in rock crevices or amongst the live rock. They have a hard exoskeleton and are equipped with strong claws that they use for feeding and defense.

Care

Emerald Crabs are relatively easy to care for, making them suitable for both beginner and advanced hobbyists. They require a tank with plenty of live rock and hiding places to feel secure. It's important to ensure that the tank is well-established with a stable environment.

While they primarily feed on algae, they may also accept meaty foods. It's crucial to monitor their feeding to ensure they are not preying on other tank inhabitants, especially if they are underfed.

Reproduction

In captivity, Emerald Crabs can reproduce if conditions are favorable. They have a complex life cycle that includes a planktonic larval stage. Breeding in home aquariums is not common, but it is possible with careful attention to water quality and feeding.

Symbiosis

While not known for any specific symbiotic relationships, Emerald Crabs can coexist peacefully with many tank inhabitants, provided they are well-fed and have ample space. They are often seen cleaning algae from coral surfaces, which can be beneficial for the corals' health.

Habitat

Phimochirus operculatus is native to the warm waters of the Caribbean and Western Atlantic. They are typically found in shallow reef environments where they can blend in with the surrounding green algae and seagrasses.