Prideaux's Hermit Crab

Geographical Origin and Habitat: Found throughout the Mediterranean Sea and the North-East Atlantic Ocean, from Norway to Cape Verde. Inhabits sandy, gravelly, or muddy sea floors at depths of 10 to 150 m.

Taxonomy: Member of the family Paguridae. Medium-small species (5-7 cm). The symbiotic anemone Adamsia palliata secretes a chitinous membrane that extends the shell, meaning the crab rarely has to find a new shell.

Social Behavior: Tight symbiont. The anemone covers the shell and positions its mouth close to the crab's claws to catch food fragments, offering a powerful stinging defense against predators (like octopuses).

Coloration and Sexual Dimorphism: Body is light brown, orange, or yellowish with reddish hues on the legs. Claws are granular and light beige. Eye stalks are slender. No visible sexual dimorphism.

Tank Setup: Requires a coolwater or temperate Mediterranean setup with a chiller. Provide a soft sandy substrate and open area for movement. The presence of the symbiotic anemone Adamsia palliata is essential.

Diet and Feeding: Omnivorous scavenger and detritivore. Feeds on small crustaceans, worms, detritus, and leftovers. Accepts mysis, brine shrimp, chopped fish, and pellets. Feeding the crab feeds the anemone.

Water Quality: Stable coolwater marine conditions (12-20°C). Intolerant of tropical temperatures. Salinity SG 1.025-1.027, pH 8.1-8.4. Strictly zero copper levels.

Compatibility and Tankmates: More reef-safe than larger Mediterranean hermit crabs. Suitable for temperate community setups. Do not house with tropical fish or tropical invertebrates.

Aquarium Breeding: Females carry eggs under their abdomen. Planktonic larval stages are highly delicate and do not survive standard home aquarium filtration systems.

Risks and Diseases: Swift decline if the symbiotic anemone dies. Overheating (above 22°C) is lethal. Highly sensitive to copper treatments and nitrogenous waste build-ups.