The Harlequin Shrimp was first scientifically described in 1852, and has also been referred to as the Painted Dancing Shrimp. It has a white body with large red, purple, or brown spots. The male is slightly smaller than the female. The female has blue tipped abdominal legs, while the legs of the male are transparent. It differs from its close cousin, H. elegans, which has pale blue spots. It has large claws (chelipeds) which are for show only; it does not use them for hunting.
The Harlequin Shrimp is best kept as mated pairs in the aquarium with moderate light. The Harlequin Shrimp can not tolerate copper or high nitrates, and iodine levels must be corect and maintained to ensure proper molting.
It is very particular about what it will eat, dining only on echinoderms, primarily starfish, and a few urchin species. It will eat starfish (Linckia, Fromia sp.) by starting at the tip of the arm and working its way to the central disc. The starfish may shed the arm, but is often mortally wounded.
As its primary source of food, you will need to supply the Harlequin Shrimp with starfish (Asterias rubens for adults, and Linckia for juveniles). The adults may also eat sea urchins.