Care Level: Advanced (due to Diet Requirements)
Reef Compatible: With Caution
General Description: The Harlequin Shrimp, also called the Clown Shrimp, is really a marvel of the saltwater hobby. There are two species, Hymenocera elegans and Hymenocera pictus. Both species have white bodies, variations of blue spots, and large claws called chelipeds that are used for show and to assist in their specialized feeding behaviors of starfish. Differences between the two species are minor; H. elegans has blotches that are more brown in color and is found in the Indian Ocean and the Red Sea, whereas H. pictus has blotches that are more red in color and is found in the Central Pacific. Harlequin shrimp reach 2″ full grown, with females being larger than males. In the wild, these shrimp are always found in pairs that rarely venture far from one another. Replicating this bond in the home aquarium is strongly recommended for success.
Diet Requirements: In the wild, Harlequin shrimp predate on starfish (specifically Linckia spp). Linckia can be expensive and a challenge to maintain as feeder starfish given their dietary requirements. Harlequin shrimp can act as a control of nuisance Asterina starfish, which often hitch hike on live rock and explode in numbers in aquaria. Chocolate Chip Starfish (Protoreaster nodosus) are inexpensive and can be kept easily in a separate tank as feeder starfish. The whole starfish need not be fed at one time; a limb can be removed and given to the Harlequin shrimp. Keeping a group of feeder starfish will extend time and recovery between limb removal per individual; this limb will be regenerated by the starfish. While Harlequin shrimp have been observed to go extended periods of time without eating, it is recommended to feed them at least once a week.
Tank Requirements: An established, minimum aquarium size of 30 gallons is recommended to house a single, or pair of, Harlequin shrimp. Maintaining stable water parameters is a component to the success of keeping this invertebrate; Harlequin shrimp are intolerable of high nitrates. Creating crevices or caves with liverock will mimic the Harlequin shrimp’s natural environment. Adding Harlequin shrimp to a reef aquarium is “with caution” because of their natural behavior to hunt starfish; they will not bother brittle starfish, however. Be sure to house Harlequin shrimp with appropriate inhabitants that will not cause stress or harm. Being rather conspicuous and having few natural defenses, Harlequin shrimp are more active at night and may be rather shy in the presence of larger, highly active fish. Absolutely avoid hawkfish and wrasses. It is imperative to take time acclimating Harlequin shrimp; we suggest via drip acclimation. Given their incredible territoriality and protectiveness towards mates (hence their semi-aggressive temperament), only one pair of Harlequin shrimp should be kept in an aquarium. Recommended water conditions: 76-78° F, dKH 8-12, pH 8.1-8.4, salinity 1.024-1.026.
Purchase Size: Small: 1/2″ to 3/4″; Medium: 3/4″ to 1″; Large: 1″ to 1-1/2″
Note: Your item may not look identical to the image provided due to variation within species. Purchase size is approximate.