Starfish Shrimp

Geographical Origin and Habitat: Very common throughout the tropical Indo-Pacific, from East Africa to Hawaii and the Gulf of California. Found in reef lagoons, strictly associated with large starfish.

Taxonomy: Member of the family Palaemonidae. Features a dorso-ventrally flattened body with short legs ending in modified hooked dactyli to grip the starfish skin. Reaches about 1-1.5 cm.

Social Behavior: Obligate commensal. Lives on its host starfish (especially Culcita, Protoreaster, or Acanthaster), feeding on the host's epidermal mucus and organic particles trapped by the star.

Coloration and Sexual Dimorphism: Display cryptic coloration mimicking the host starfish: often deep red, purple, or brown with a white or clear stripe on the back. Females are noticeably larger than males.

Tank Setup: Requires an established, mature reef aquarium. It is essential to keep suitable large sea stars (such as Culcita novaeguineae or Protoreaster nodosus) to sustain this shrimp in captivity.

Diet and Feeding: Scavenger and commensal. Feeds on host mucus. In captivity, target-feed with fine frozen foods (cyclops, reef plankton) directed near the shrimp on the host's body.

Water Quality: Stable reef parameters. Salinity SG 1.023-1.025, pH 8.1-8.4, temperature 22-28°C. Strictly zero copper levels. Highly sensitive to rapid salinity drops.

Compatibility and Tankmates: Completely peaceful. Keep only with peaceful fish that do not pick at starfish. Avoid predatory or curious fish (e.g. hawkfish, puffers, wrasses).

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

Risks and Diseases: Fast decline and death if the host starfish dies or suffers from tissue necrosis. Highly sensitive to copper treatments and salinity shock.