Shrimps Crabs and Lobsters: Decapoda

Physical characteristics: Adult Harlequin shrimp measure about 2 inches (50 millimeters) in length. The claws on the second pair of legs are very large, distinctly flat, and platelike in shape. Both the body and claws have bright purple markings or red blotches on a white or cream-colored background.

Geographic range: This species is found along the shores of East Africa, the Red Sea to Indonesia, and across northern Australia to Hawaii, Panama, and the Galápagos Islands.

Habitat: This species lives in and hides among coral reefs.

Diet: Harlequin shrimp pry sea stars off coral reefs with their large, flat claws and eat them.

Behavior and reproduction: Pairs are territorial. Single individuals are much more active than those in pairs.

Harlequin shrimp pry sea stars off coral reefs with their large, flat claws and eat them. (Secret Sea Visions/Peter Arnold, Inc.)

Adult males and females live and defend their territory together. Females molt every eighteen to twenty days and mate soon after. They produce about one thousand eggs at a time. Eggs hatch within eighteen days. The larvae are well developed and spend a short time floating in the water with other plankton. Plankton is made up of plants and animals that live in open water and are at the mercy of ocean currents.

Harlequin shrimps and people: Harlequin shrimp are popular pets because they are easy to breed and raise in captivity. They might also play a role in conserving coral reefs because they eat small, coral-eating crown-of-thorns sea stars.

Conservation status: The World Conservation Union (IUCN) does not consider this species to be threatened or endangered. ∎