Care
This small, heavily-armoured green crab is primarily herbivorous, preferring a diet of various types of algae, including adherent fleshy green algae, some bubble algae, and even coralline algae " a most unusual diet for a crab. It will require supplementary feeding with small amounts of meaty fare now and again, but it will need an ongoing supply of greenfoods to thrive. It is therefore essential that this crab is only added to mature aquaria containing plenty of live rock for it to graze upon. In the wild, Emerald Crabs inhabit algae-covered rocky coastlines and seagrass beds, where they are well camouflaged. Many aquarists keep this species very successfully in a reef setting, but there are reports of occasional specimens picking on sessile invertebrates; however, this usually only occurs when the crab does not have a plentiful supply of greenfoods and it looks elsewhere for food. A refugium can be beneficial in this respect " marine algaes can be cultured on rocks and rotated with those in the main aquarium to ensure an ongoing supply of food. This crab is often sold as part of a "clean up crew", and although it will browse on uneaten bits of food, it still most definitely requires continuous specific feedings of greenfoods. When well fed, most Emerald Crabs are very tolerant of their tankmates and are highly compatible in reef situations. They should not be trusted with very small fish though. More than one may be kept in the same tank providing it is spacious and there is an abundance of food and hidey holes. May also be seen on sale as the Emerald Mithrax Crab. *Never use copper-based treatments in the invertebrate aquarium.*
Feeding
Requires a primarily herbivorous diet, supplemented with the occasional meaty meal (Mysis, finely chopped prawns etc). There should always be a variety of marine algae (micro and macro) on offer, and greenfoods such as dried seaweed/Nori can also be given.
Breeding
Emerald Crabs have spawned in the home aquarium, however, the resultant miniscule larvae are extremely sensitive and difficult to feed - there are currently no successful reports of them being raised to adulthood in captivity.
