Emerald Crab

The Emerald Crab (Mithraculus sculptus) is the established biological control of choice for Valonia bubble algae – a common reef pest that can proliferate rapidly on live rock, smothering corals and reducing water quality. Emerald Crabs actively seek out and consume bubble algae, popping and eating individual cells before they can release spores that spread the infestation. They also graze on a variety of other nuisance algae types and will scavenge uneaten food from the substrate. Generally reef safe with corals; occasional reports of opportunistic nipping at soft coral polyps in heavily stocked or underfed systems. Provide supplemental meaty foods if algae availability is limited. A practical, functional addition to any reef system experiencing algae management challenges.