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Harlequin shrimp

Hymenocera picta

A visually spectacular marine shrimp with paddle-like claws, famous for feeding exclusively on live starfish. Geographical Origin and Habitat: Hymenocera picta, the harlequin shrimp, is...

Taxonomy
Class:Malacostraca
Order:Decapoda
Family:Palaemonidae
Genus:Hymenocera
Species:Hymenocera picta

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Water Temperature

22 - 28 °C

pH Value

8.1 - 8.4

Water type

Marine

Invertebrate type

Marine shrimp

Adult size

5 cm

Minimum group

>= 1

Ecological role

Scavenger

Species description

Geographical Origin and Habitat: Hymenocera picta, the harlequin shrimp, is native to the tropical waters of the Central and Eastern Indo-Pacific, ranging from the eastern coast of Africa to Hawaii and the Gulf of California. They inhabit coral reefs and shallow rocky crevices at depths of 1 to 20 meters, usually hiding in pairs under ledges during the day.
Taxonomy: A member of the family Hymenoceridae. This shrimp is famous for its unique morphology, featuring large, flattened, leaf-like appendages on its claws (chelipeds) and head. Females are noticeably larger than males, with adults reaching a maximum length of 3 to 5 centimeters (1.2 to 2 inches).
Social Behavior: They almost always live in dedicated male-female pairs. These pairs exhibit cooperative hunting behavior, working together to overpower, flip, and drag large starfish back to their shelter to feed. They are generally peaceful towards other tankmates and ignore corals.
Coloration and Sexual Dimorphism: The body has a cream-white or light pink base color, decorated with large, colorful spots of purple, blue, red, and pink, outlined in a darker border. Females are larger than males and possess colorful plates under their abdomen, which are absent or reduced in males.

Care, breeding and tankmates

Tank Setup: A well-established reef tank of at least 15 gallons (50 liters) is required. The tank must feature plenty of live rock to create caves and shaded hiding spots. They prefer gentle to moderate water flow and stable salinity levels. Avoid predatory fish.
Diet and Feeding: An obligate carnivore that feeds ONLY on starfish (such as Asterina, Linckia, and chocolate chip starfish, Protoreaster nodosus). They will not eat flakes, pellets, or frozen shrimp. A steady supply of live starfish (one medium starfish every 1-2 weeks) is required.
Water Quality: Extremely sensitive to water quality. Keep specific gravity stable at 1.023 to 1.025, temperature at 24 to 27 °C (75 to 81 °F), and pH between 8.1 and 8.4. Copper in the water is deadly. Keep nitrates as close to zero as possible.
Compatibility and Tankmates: Reef-safe for corals and other non-starfish invertebrates. Keep in mated pairs. Do not house with aggressive fish or crustacean predators like hawkfish, wrasses, triggerfish, or pufferfish, which will quickly eat the shrimp.
Aquarium Breeding: Breeding is possible in a home aquarium when kept as a pair. The female carries eggs under her tail, which hatch into free-swimming larvae. However, rearing the larvae is exceptionally difficult due to their planktonic stage and specific food requirements.
Risks and Diseases: The primary risk is starvation if the aquarist cannot provide live starfish. Molting failure is another risk, which can be minimized by maintaining correct levels of iodine and calcium in the water to support exoskeleton development.

Geographic Origin and Distribution

Hymenocera picta, the harlequin shrimp, is native to the tropical waters of the Central and Eastern Indo-Pacific, ranging from the eastern coast of Africa to Hawaii and the Gulf of California. They inhabit coral reefs and shallow rocky crevices at depths of 1 to 20 meters, usually hiding in pairs under ledges during the day.

Origin

Cosmopolitan or introducedNorth AmericaAfrica and MadagascarTropical oceans and reefs

Invertebrate profile

Diet
Carnivore
Hymenocera picta is primarily an omnivorous scavenger that constantly forages for detritus, biofilm, and leftover food among the substrate. In captivity, their diet should be supplemented with high-quality sinking pellets, frozen mysis, and occasional vegetable matter. A diverse and rich diet ensures robust molting and brilliant coloration.
Ecological role
Scavenger
Playing a critical role in the aquatic food web, Hymenocera picta acts as a macro-detritivore that breaks down organic materials. Their constant scavenging significantly reduces the accumulation of decaying matter, thereby improving overall water quality. In reef or planted tanks, they often act as meticulous cleaners of the aquascape.
Shock sensitivity
High
Hymenocera picta is highly susceptible to osmotic shock caused by rapid shifts in specific gravity, temperature, and pH. Sudden changes can compromise their delicate osmoregulatory systems, often leading to immediate fatalities or failed molts. A diligent drip acclimation process taking at least one to two hours is vital for successful introductions.
Calcium and minerals
High
To successfully regenerate their chitinous exoskeleton during a molt, Hymenocera picta requires consistent availability of dissolved calcium, magnesium, and trace iodine. Poor mineral content in the water column can result in "white ring of death" or the inability to fully shed their old shell. Regular water changes and appropriate mineral supplementation are essential for their survival.
Molting
Periodic
Molting is the most precarious time in the life cycle of Hymenocera picta, during which it will hide until its new exoskeleton hardens. Aquarists will often find complete, transparent molts in the tank, which should be left in the water as the shrimp will consume it to reclaim lost minerals. Never disturb or force a shrimp out of hiding during this vulnerable phase.
Reproduction
Oviparous
Under optimal water conditions and with plenty of food, Hymenocera picta can readily breed in captivity. Females can often be seen carrying clutches of eggs (berried) beneath their pleopods until they hatch into miniature shrimp or planktonic larvae. Providing dense moss or hiding spaces greatly increases the survival rate of the offspring.
Compatibility & tankmates
Peaceful
Hymenocera picta is best kept in dedicated invertebrate setups or alongside small, peaceful nano fish. They are at high risk of predation from cichlids, larger wrasses, hawkfish, and puffers, which will readily hunt them. When kept with appropriate tank mates, they will confidently display their active and engaging behaviors.

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

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Last updated: 06/30/2026