Harlequin Emerald Crab

Harlequin Emerald Crab needs rockwork that provides both places to forage and sheltered gaps. Its patterned appearance is a reason to keep and observe it, but the emerald name alone does not establish reliable control of a particular nuisance alga.

Offer a mixed diet with algae-based marine food and small meaty portions, checking which items the crab collects and eats. Place supplements within reach when fish or other scavengers intercept food. A newly set-up or heavily cleaned aquarium may offer little natural grazing, so visible activity should not replace feeding observations.

Plan conservatively around delicate tankmates. Marine crabs can be opportunistic feeders, and full feeding does not guarantee compatibility with small animals or coral tissue. Keep a practical way to separate the crab if persistent grabbing or damage develops, and provide cover during moulting.