Without a doubt, the Harlequin Shrimp is one of the most strikingly beautiful species of shrimp available to a marine enthusiast. The Harlequin Shrimp is even more intriguing when its unique feeding habits are considered.

The Harlequin Shrimp is considered to be reef safe. However, in reefs that include Sea Stars or Urchins, the Harlequin Shrimp should not be present, since it will prey on these animals. Harlequin Shrimp are often kept in pairs. They prefer moderate lighting and rocky substrates, or substrates made of coral rubble. Plenty of hiding places should be provided, as most Harlequin Shrimp are shy and retiring. They tend to spend most of the day in hiding, coming out at night to feed. Harlequin Shrimp have a highly specialized diet, which makes them rather difficult for some people to keep. In the wild, they consume the tube feet of Linckia species sea stars, particularly the Comet and Blood Spotted Stars. In captivity, Harlequin Shrimp may not flourish unless sea stars that they may prey on are placed in their tanks. You may need to try several different types before finding a suitable food source. A single star may provide weeks of food for these shrimp. Unless you are sure you will be able to provide a regular supply of prey for your Harlequin Shrimp, you may wish to consider a different shrimp species. Because they are also considered to be rather delicate, Harlequin Shrimp may not be a good choice for beginning marine aquarists.

A full-grown Harlequin Shrimp normally measures 1 to 1.5 inches. Normally, specimens from the Indian Ocean are on the shorter side of the range, while specimens collected from the Pacific grow a little larger. Their bodies are relatively stocky or broad. The entire Harlequin Shrimp is white to whitish pink in color. The body is splashed with brown, purplish, pink, or reddish spots. Pink spots are often edged in purple. Some specimens have spots that appear almost orange in color. The claws on a Harlequin Shrimp are tapered at the ends, and often have purple bands of color over them. Harlequin Shrimp have flattened antennae, which resemble leaf shapes, and can be moved from side to side. The eyes are located at the ends of stalks.

Harlequin Shrimp are native to the Tropical Indo Pacific, and are most often found in the Central Pacific, including the Hawaiian Islands. Many captive specimens are also collected from the Indian Ocean.

Moderate lighting and temperatures between 72 and 78 degrees Fahrenheit (23 to 26 degrees Celsius) are acceptable for Harlequin Shrimp. A pH value of 8.3 or 8.4 and a specific gravity between 1.023 and 1.025 are also ideal. Levels of iodine should be maintained to avoid problems with molting. Copper based medications should not be used in tanks where Harlequin Shrimp are housed. Extreme nitrate levels are also unacceptable. Harlequin Shrimp are best kept in pairs, and should not be kept with sea stars or urchins that are not intended to be food. Plenty of hiding places should be provided, and substrates should be made of rocks or coral rubble. Harlequin Shrimp should be fed a diet of sea stars, as this is their natural nourishment. Some will accept other food items in captivity. It is widely agreed that Linckia species are ideal for juvenile Harlequin Shrimp, while adults are usually offered the species Asterias rubens.

Female Harlequin Shrimp are slightly larger than males. Females also have blue tips on their abdominal legs, while males have transparent legs.