Description
Blue Eyed Hermit Crab (Clibanarius tricolor)
(Also known as Tricolor Hermit Crab, Blue-Legged Hermit Crab, or Caribbean Blue Hermit Crab)
Overview
The Blue Eyed Hermit Crab (Clibanarius tricolor) is a small, colourful marine crustacean highly prized for its bright appearance and excellent cleaning abilities. Recognisable by its electric blue legs, white banding, and distinctive turquoise eyes, this hermit crab is both attractive and functional in reef aquariums. A natural scavenger, it feeds on algae, detritus, and leftover food, helping maintain a clean and balanced ecosystem. Hardy, active, and reef safe, the Blue Eyed Hermit Crab is a perfect addition to most marine cleanup crews.
Origin
Native to the Caribbean Sea, Gulf of Mexico, and Western Atlantic Ocean. Typically inhabits shallow coral reefs, sandy lagoons, and tidal zones, where it moves between rocks and coral rubble in search of food and empty shells.
Feeding
An omnivorous scavenger, Clibanarius tricolor constantly grazes on biofilm, algae, and detritus. Supplement its natural diet with 3–4 feedings per week of:
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Algae wafers or marine pellets
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Mysis shrimp or finely chopped seafood
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Seaweed sheets (nori)
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Leftover fish food
Feeding ensures the crab remains healthy and reduces competition or aggression over food and shells.
Lighting
Low to moderate lighting. This species does not depend on light and will thrive under typical reef illumination, often foraging during both day and night.
Water Flow
Moderate flow. Provide steady circulation that keeps detritus suspended but allows calm areas where the crab can rest and scavenge comfortably.
Placement & Habitat Setup
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Provide a mature tank with plenty of live rock for grazing and hiding.
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Include a variety of empty shells of different sizes and shapes to accommodate growth and reduce shell-related aggression.
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A sandy or fine-gravel substrate allows for natural movement and burrowing behaviour.
Tank Mates
Reef safe. Excellent companion for:
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Peaceful reef-safe fish (clownfish, gobies, tangs, blennies, etc.)
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Other small hermit crabs and shrimp (with adequate space and shells)
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Corals, anemones, and most invertebrates
Use caution with:
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Large, aggressive crabs or carnivorous fish (triggers, puffers, wrasses) that may prey on them
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Snails — while generally peaceful, C. tricolor may occasionally evict snails for their shells if replacements are unavailable
Aggression
Peaceful, with mild opportunism. Generally non-aggressive, but shell disputes can occur if spare shells are limited. Always provide plenty of empty shells to reduce competition.
Experience Level
Beginner. The Blue Eyed Hermit Crab is hardy, easy to care for, and highly beneficial for reef maintenance — ideal for new and experienced aquarists alike.
Water Parameters
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Temperature: 24–27°C (75–81°F)
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pH: 8.1–8.4
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Salinity: 1.024–1.026 SG
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Ammonia / Nitrite: 0 ppm
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Nitrate: <10 ppm
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Tank Size: Minimum 20 litres (5 gallons) for small groups; larger tanks preferred for stability
Lifespan & Size
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Size: Up to 2.5 cm (1 inch) including shell
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Lifespan: 2–4 years in captivity with proper diet and stable water quality
Reef Compatibility
Fully reef safe. The Blue Eyed Hermit Crab is a valuable member of any cleanup crew, consuming nuisance algae, detritus, and leftover food without harming corals or other invertebrates. Its vivid colours, energetic behaviour, and low maintenance make it a top choice for reef aquariums of all sizes.
