Emerald Crab
Emerald Crab
Scientific Name: Mithraculus sculptus
Common Name: Emerald Mithrax Crab, Green Clinging Crab
Origin: Caribbean & Western Atlantic
Why Emerald Crabs Are Popular
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Excellent algae eaters – especially bubble algae (Valonia spp.)
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Great addition to reef clean-up crews
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Reef-safe with caution – generally peaceful scavengers
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Nocturnal and highly active at night
Care Level
Easy – Hardy, low maintenance
Temperament
Peaceful scavenger; may become opportunistic if underfed
Reef Safe
Safe with corals
May pick at polyps or small inverts if starving
Tank Requirements
| Requirement | Details |
|---|---|
| Minimum Tank Size | 20+ gallons |
| Temperature | 72–78°F |
| pH | 8.1–8.4 |
| Salinity | 1.023–1.025 |
| Diet | Algae, leftover food, seaweed, sinking pellets |
Size
Up to 2–2.5” body width
Feeding
Primarily herbivorous. Will graze on:
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Hair algae
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Film algae
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Bubble algae
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Leftover fish food
Supplement with nori, pellets, or algae wafers to prevent coral picking.
Notes
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Best kept singly or in small groups (depending on tank size)
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Provide plenty of rockwork to climb and hide in
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Excellent addition to reef tanks struggling with nuisance algae
