Arethusa Hermit Crab

Geographical Origin and Habitat: Indian Ocean: coasts of southern India, Sri Lanka, and the Andaman Sea. Commonly found in tide pools, rocky shores, and shallow coral reefs at depths from 0 to 10 meters.

Taxonomy: Family Diogenidae, genus Clibanarius. Hermit crab with a soft abdomen protected by a gastropod shell, which it changes as it grows. Grows to 3.0 cm.

Social Behavior: Peaceful and social scavenger. Spends its time crawling over rocks and sand searching for algae and organic detritus.

Coloration and Sexual Dimorphism: Commonly found along shallow reefs climbing on stable rocky substrates. Sexes are indistinguishable externally; shell selection is based purely on size.

Tank Setup: Suitable for small tanks starting from 20.0 liters. Provide stable rockwork and keep a supply of empty shells of various sizes for growth.

Diet and Feeding: Omnivorous scavenger. Constantly consumes nuisance algae, organic waste, and leftover fish food on the substrate.

Water Quality: Stable marine chemistry parameters: temperature 22.0-26.0 °C, pH 8.1-8.4, specific gravity 1.021-1.025. Sensitive to copper.

Compatibility and Tankmates: 100% reef-safe. Excellent member of the clean-up crew. May attack small live snails if empty shells are not provided.

Aquarium Breeding: Releases microscopic zoea larvae into the water column; rearing them to settlement in aquariums is virtually impossible.

Risks and Diseases: Extremely sensitive to copper treatments. Lack of spare shells causes stress and aggression toward snails.