Tubular Hermit Crab

Geographical Origin and Habitat: Common in the Mediterranean Sea and along the warm East Atlantic coast (from Spain to Mauritania, including the Azores, Madeira, and Canary Islands). Inhabits shallow rocky substrates.

Taxonomy: Member of the family Diogenidae. A tiny hermit crab species, growing to 1-1.5 cm. Unlike most hermits, it prefers to inhabit empty calcareous tubes of vermetid snails (e.g. Petaloconchus) cemented to rocks.

Social Behavior: Peaceful and sedentary. Due to its preference for fixed tubes, it leads a less mobile lifestyle than other hermits, emerging from its tube to feed on surrounding particles.

Coloration and Sexual Dimorphism: Reddish-brown or greyish body with small white spots and orange bands on the legs. Displays marked sexual color dimorphism, especially on the claws which are more colorful in males. No visible sexual dimorphism.

Tank Setup: Suitable for Mediterranean or temperate marine aquariums of 5 gallons or larger. Provide live rock with small holes or vermetid tube colonies. Small shells must be offered if tubes are unavailable.

Diet and Feeding: Herbivore and detritivore. Scrapes microalgae from nearby rocks or filters suspended detritus from the water. Accepts fine sinking pellets and crushed frozen foods.

Water Quality: Requires well-oxygenated water and stable parameters. Salinity SG 1.025-1.028 (standard for Mediterranean), pH 8.1-8.4, temperature 16-24°C. Highly sensitive to copper.

Compatibility and Tankmates: 100% reef-safe. Perfect scavenger for temperate biotopes. Compatible with peaceful small fish. Harmless to corals and macroalgae.

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

Risks and Diseases: Molting failure if calcium, magnesium, or iodine levels are depleted. Vulnerable to predation or stress if evicted from its tube.