The Harlequin Shrimp have a white body with large light blue spots, and the males are slightly smaller than the female. It differs from its close cousin. 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 an aquarium with moderate light. As mentioned Females Harlequin Shrimp grow larger than Males, Males also lack the blue tips of the pleopods, which is present in adult females (the females have a coloured/ patterned belly where as the males have a plain belly).
It is very particular about what it will eat, feeding 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.
The Harlequin Shrimp can not tolerate copper or high nitrates, and iodine levels must be correct and maintained to ensure proper molting.