Depth
Dardanus · Crustaceans (Crabs, Shrimps & Lobsters)

Red Hermit Crab

Dardanus calidus

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Reef & Open
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Phylum Arthropoda
Class Malacostraca
Genus Dardanus
Species calidus

Crustacean

Identification & Biology

  • IdentificationA striking hermit crab with bright scarlet to orange-red legs and claws. The left claw is larger than the right and is used to block the shell entrance when retracted. Eyes on short stalks with blue or green highlights.
  • SizeBody length up to 10 cm (excluding shell). Occupies medium to large gastropod shells.
  • Social HabitSolitary. Like the greater hermit crab, often found with symbiotic anemones attached to its shell. Regularly upgrades to larger shells as it grows.
  • HabitatRocky reefs, mixed substrates, and seagrass meadows. Prefers areas with plentiful empty shells for housing.
  • Depth5 to 80 m. Common between 10 and 40 m.
  • Feeds OnDetritus, carrion, algae, and small invertebrates. An opportunistic scavenger and omnivore.
  • DistributionMediterranean Sea and adjacent eastern Atlantic. Common in Maltese waters.
  • DescriptionDardanus calidus is one of the most photogenic crustaceans on Mediterranean reefs, its vivid red colouring making it easy to spot against rocky and sandy substrates. Like its relative the greater hermit crab, it frequently hosts Calliactis parasitica anemones on its borrowed shell. The anemones are carefully transferred when the crab switches to a new, larger shell.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting reef & open environments. Active from the surface down to 40m depth.

Where Malta divers have spotted this species

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Sightings are logged by divers using our What Did You See? dive-log tool. View the full live sightings map.

Detail

Preferred Environment

Reef & Open habitats, typically at depths of 0-40m. Most commonly encountered by divers at the shallower end of its range.

Encounter Tips

Best approached slowly and calmly. Avoid casting shadows directly over the animal. Neutral buoyancy and patience increase encounter success significantly.

Red Hermit Crab species card

Biology

Behaviour & Diet

Feeding Strategy

Omnivorous scavenger feeding on algae, detritus, and small invertebrates on rocky substrates. Frequently observed picking over Posidonia leaf litter for organic material.

Omnivorous scavenger

Reproduction

Females carry egg masses on their pleopods inside the gastropod shell until hatching. Larvae develop through several planktonic stages before settling.

Egg carrier

Behaviour & Defence

Retreats fully into its borrowed gastropod shell when threatened, blocking the aperture with its larger cheliped. Readily abandons a shell for a larger one as it grows.

Shell retreat

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Dardanus calidus. All are accessible on a guided dive with diveshack.

5-30m
North Malta

Cirkewwa

Rocky reef with caves, arches and ledges hosting a rich diversity of reef species.

View dive site ›
5-50m
Gozo

Blue Hole

One of the Med's most famous reef dive sites. Rocky walls and archways covered in life.

View dive site ›
18-36m
South Malta

Um El Faroud

The wreck lies on a sandy bottom surrounded by rocky reef -- a diverse habitat attracting reef species.

View dive site ›
IUCN Red List Least Concern

Conservation Status

This species is assessed as Least Concern on the IUCN Red List. Mediterranean populations face ongoing pressure from fishing activity, habitat degradation, and climate-driven changes to prey availability.

Source: iNaturalist Guide #888
by Lesley Clements (CC BY-SA)
diveshack Mediterranean Marine Life guide