Mediterranean Hermit Crab

Geographical Origin and Habitat: Widely distributed throughout the Mediterranean Sea and neighboring warm eastern Atlantic coasts. Inhabits sandy, muddy, or rocky substrates from shallow waters down to 40 meters.

Taxonomy: Member of the family Diogenidae. A medium-sized species growing to around 3-4 cm in total length. Features subequal claws covered in small tubercles and fine hairs.

Social Behavior: Peaceful, social, and an active bottom-dwelling scavenger. Spends its time digging in fine sand or climbing rockwork looking for organic matter. Harmless to fish.

Coloration and Sexual Dimorphism: Body and walking legs are reddish-orange, brick-red, or reddish-brown. It is characterized by striking, bright blue or light blue eyes. No visible sexual dimorphism.

Tank Setup: Suitable for Mediterranean or temperate marine aquariums of 10-15 gallons or larger. Prefers a sandy substrate and live rock. Medium-sized empty shells must be supplied.

Diet and Feeding: Omnivorous scavenger. Consumes microalgae, detritus, and leftover fish food. Accepts sinking pellets, spirulina wafers, and chopped frozen foods.

Water Quality: Stable temperate marine parameters. Salinity SG 1.025-1.028, pH 8.1-8.4, temperature 15-24°C. Highly sensitive to copper treatments and elevated nitrates.

Compatibility and Tankmates: Ideal for Mediterranean community tanks. Compatible with temperate fish (e.g. blennies, gobies) and other invertebrates. May target live snails if empty shells are lacking.

Aquarium Breeding: Microscopic larval stages are pelagic and complex, and do not survive standard home aquarium filtration systems.

Risks and Diseases: Low iodine or calcium leading to failed molts. Lack of suitable replacement shells causes high stress and potential mortality.