Mountain 'opae are a spineless endemic freshwater shrimp. 'Opae can grow up to two inches in length. Female 'opae have a blue-green tinge,. large body and are darker in color than the males. 'Opae pinchers might have bristle-like hairs that form a hand to filter food from water.

Habitat 'Opae climb upstream. They are in the middle to the upper parts of the streams on Kaua'i, O'ahu, Moloka'i and the Big Island.

In the fastest part of the streams, they live between rocks and boulders.

Life Cycle Female 'opae carry their eggs under their tail until they are ready to hatch, which takes about two months. The larvae are washed downsteam to the ocean. .After three months of developing in the ocean, 'opae return to the streams and crawl upstream to the mountains. 'Opae were an important food for Hawaiians during the winter when they couldn't go out to fish.

Diet In fast flowing water, 'opae turn toward the current. Its front legs, with fan-like hairs, forminto baskets.

The baskets catch food particles, and the'opae shoves the food in its mouth. In slower water, the 'opae uses its pinchers to pick up food from the stream floor.