Family: Atyidae
Harlequin Shrimp — Caridina wolterecki from Sulawesi's ancient lakes, porcelain white with reddish-brown broken bands. Needs warm hard alkaline water at 26-30 °C (pH 7.5-8.5, 7-12 dGH), clean and well-oxygenated; a specialist species.
Harlequin Shrimp is the strikingly patterned Caridina wolterecki from the ancient lakes of Sulawesi, Indonesia — Lake Poso and the Malili lake system — where it clings to rocks in warm, hard, alkaline water that would kill the soft-water bee shrimp. Its body is porcelain white broken by irregular reddish-brown bands and blotches, a harlequin pattern no other popular shrimp matches. It is a specialist in every sense: 26-30 °C, pH 7.5-8.5 and 7-12 dGH, strong light encouraging the algae it grazes, and excellent oxygenation. In the aquarium it needs a dedicated Sulawesi setup — often escarpment-style rock aquascapes with very clean, well-filtered water — and accepts algae, biofilm and spirulina-based foods. It grows to 2-3 cm, is shy at first but becomes bold in stable conditions, and breeds in freshwater, females carrying 10-20 relatively large eggs. Sensitive to nitrate and to sudden changes, it rewards the specialist with one of the most beautiful patterns in the hobby. Never mix its hard alkaline regime with soft-water caridinas.
For experienced keepers. Very peaceful; groups of 10 or more.
Aim for 26–29 °C. Constant 26–29 °C — a heater with a guard is mandatory; 26–29 °C stable range.
Expect 2–2.5 cm as an adult, living bottom — grazing rock and sponge surfaces. A 30 L tank or larger gives it room.
Algae and aufwuchs grazer; spirulina foods. Vary the menu — quality flakes or pellets plus frozen or live foods.
Yes, with care. Very peaceful — pair it with Other Sulawesi lake shrimp — Shared hard alkaline chemistry — the only safe mix, Sulawesi snails (Tylomelania) — Same lake system, same parameters and skip Soft-water Caridina (bee shrimp lines) — Opposite chemistry; one side dies, Copper-based medications — Lethal to all invertebrates, Any nitrate-prone setup — Sulawesi shrimp demand near-zero nitrate.
Native to Lake Towuti, Sulawesi, Indonesia — endemic, where it lives in deep, hot, alkaline crater lake with rocky shores. Gentle current; High oxygen.
In the aquarium: breeds in freshwater. The female carries 10-20 relatively large eggs for about four weeks; hatchlings are well-developed. Success depends on rock-solid parameters and clean water rather than any trick.. Females are larger and deeper with broader banding; males slimmer with finer lines..