Emerald crab

Care at a glance

The emerald crab is bought for one specific reason: it is one of the few animals that tackles bubble algae, those bladder-like green spheres you can never fully remove by hand. With its spoon-shaped claws it picks them loose and eats them.

So it is a tool with a mind of its own. As long as there are algae it does its job; once they run out it goes looking for other food, and a sleeping fish, a shrimp or a soft coral may be next. So feed it once the algae are gone, and stick to one or two animals in a normal tank. It is most active at night and hides during the day.

Good to know

• Active at night

Best not combined with

• Peacock mantis shrimpOdontodactylus scyllarus

Related species

• Porcelain anemone crabNeopetrolisthes maculatus
• Saron shrimpSaron marmoratus
• Harlequin shrimpHymenocera picta
• Tuxedo urchinMespilia globulus
• Pistol shrimp (randalli)Alpheus randalli
• Sand sifting starfishAstropecten polyacanthus