Scarlet reef hermit crab with bright red legs

KNOWLEDGE, CULTIVATED.

Cleanup Crew

Choose the right workers for the job: algae grazers, leftover-food scavengers and sand-surface feeders have different needs.

Useful: a practical addition when properly fed. Caution: specialist care or compatibility risks. Start small and add only what your reef can sustain; cleanup animals recycle waste rather than exporting nutrients. Maintain filtration and routine cleaning.

Adult sizes are approximate: snail sizes describe shells, crab sizes state the measurement used, and star sizes include arms. Confirm the supplier’s species, acclimate to matched conditions and quarantine appropriately; do not use coral dips on cleanup animals.

Written by Christian, Signature FragsLast reviewed:

Hermit crabs

All cleanup crew
Scarlet reef hermit — Paguristes cadenati

Scarlet reef hermit reference photograph.

Scarlet reef hermit

Useful

Paguristes cadenati

Usually a gentle grazer; every hermit still carries some snail risk.

Quick ID
Bright red legs and yellow eyestalks. Confirm the species: “red leg” is also used for other hermits.
Typical adult size
About 2–3 cm across the exposed animal; shell adds bulk.
Useful work
Picks at short filamentous algae, biofilm and leftover food on rock.
Feeding & care
Offer varied empty shells and small algae-based or marine foods when natural grazing is sparse.
Best fit
A small mixed cleanup crew with adequate food and space.
Watch out for
Can take snail shells or fight other hermits. Spare shells reduce competition but cannot guarantee snail safety.
Research sources
Dwarf blue-leg hermit — Clibanarius tricolor

Dwarf blue-leg hermit reference photograph.

Dwarf blue-leg hermit

Caution

Clibanarius tricolor

Useful small scavenger; snail-shell theft is a real trade-off.

Quick ID
Blue legs with coloured banding; tiny crab living in a borrowed snail shell.
Typical adult size
About 2–3 cm including occupied shell; varies with shell choice.
Useful work
Grazes algae films and short filaments, and picks up leftover food.
Feeding & care
Provide several suitable spare shells per crab; feed small mixed marine foods if the aquarium becomes too clean.
Best fit
Rockwork and sand margins; stock lightly rather than buying a large fixed package.
Watch out for
May kill snails or evict smaller hermits. Do not assume its small size makes it harmless.
Research sources
Electric blue / blue-knuckle hermit — Calcinus elegans

Electric blue / blue-knuckle hermit reference photograph.

Electric blue / blue-knuckle hermit

Caution

Calcinus elegans

A colourful worker with stronger claws than tiny dwarf hermits.

Quick ID
Electric blue walking legs with dark bands; spotted claws and vivid antennae.
Typical adult size
Around 4–5 cm with shell; larger than most dwarf hermits.
Useful work
Picks at filamentous algae and scavenges food on rock and rubble.
Feeding & care
Supply larger spare shells and mixed algae-based and meaty marine foods; secure frags.
Best fit
Established reefs with room to forage and robust tankmates.
Watch out for
May attack snails, bully small hermits or disturb unsecured frags.
Research sources
Dwarf zebra / left-handed hermit — Calcinus laevimanus

Dwarf zebra / left-handed hermit reference photograph.

Dwarf zebra / left-handed hermit

Caution

Calcinus laevimanus

Useful omnivore; monitor shell competition.

Quick ID
Black-and-white banded legs and a noticeably larger left claw.
Typical adult size
Usually around 2–3 cm with shell; shell dimensions vary.
Useful work
Grazes films and short algae and searches crevices for food scraps.
Feeding & care
Offer differently shaped spare shells and small marine foods when grazing is limited.
Best fit
A lightly stocked mixed crew on rockwork.
Watch out for
The large claw can evict snails or smaller hermits. “Zebra hermit” names are not always species-specific.
Research sources
Mexican red-leg hermit — Clibanarius digueti

Mexican red-leg hermit reference photograph.

Mexican red-leg hermit

Caution

Clibanarius digueti

Small scavenger; distinguish it from the scarlet reef hermit.

Quick ID
Reddish legs and conspicuous blue-toned eyes; shop names overlap with other red hermits.
Typical adult size
Roughly 2–3 cm with shell; approximate aquarium size.
Useful work
Picks at algae films, short filaments and leftover food.
Feeding & care
Provide spare shells and a mixed marine diet as needed; observe individual behaviour.
Best fit
Rockwork and rubble in a small, well-fed mixed crew.
Watch out for
Can compete for shells and harass snails. Red legs alone do not confirm the species.
Research sources
Halloween hermit — Ciliopagurus strigatus

Halloween hermit reference photograph.

Halloween hermit

Caution

Ciliopagurus strigatus

A larger, more disruptive omnivore rather than a default nano cleaner.

Quick ID
Orange-red and pale bands around the legs; often occupies a cone-shaped shell.
Typical adult size
Around 5–6 cm with shell; allow additional room for its reach.
Useful work
Scavenges food and grazes some algae over rock and sand.
Feeding & care
Supply suitable elongated spare shells, mixed marine foods and firmly fixed frags.
Best fit
Larger established reefs where its behaviour can be monitored.
Watch out for
Can kill snails, compete with other hermits and shift loose frags. Individual reef compatibility varies.
Research sources
Close-up of coral tentacles in purple, pink, blue and green

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