Arrow Crab

Geographical Origin and Habitat: Widely distributed in reef crevices and back-reefs of the tropical Western Atlantic, from North Carolina to Brazil. Commonly found near sea anemones.

Taxonomy: Member of the Inachidae family. Characterized by an elongated snout (rostrum) showing iridescent longitudinal stripes and long legs. Body reaches 10 cm including legs.

Social Behavior: Territorial and aggressive towards other arrow crabs. Active and opportunistic scavenger that crawls over rocks in search of prey.

Coloration and Sexual Dimorphism: Body has gold, brown, and white pinstripes; claw tips are colored violet-blue. Adult males have longer claws than females.

Tank Setup: Minimum tank size of 100 liters with plenty of live rock.

A secure lid is required: as this crab is a capable climber and might try to escape.

Diet and Feeding: Carnivorous omnivore. Excellent biological control for bristle worms and flatworms. Readily accepts frozen foods (mysis, brine shrimp), chopped seafood, and sinking pellets.

Water Quality: Specific gravity 1.023-1.025, pH 8.1-8.4, temperature 22°C-27°C. Requires regular iodine additions to aid in successful molting.

Compatibility and Tankmates: Safe with corals. May harass tiny ornamental shrimp or very small, sleeping fish if underfed.

Aquarium Breeding: Female carries eggs under her abdomen. Upon hatching, pelagic larvae are released, which rarely survive standard aquarium filtration.

Risks and Diseases: Extremely vulnerable to predation during the molting phase. Highly sensitive to copper treatments and sudden osmotic shock.