O'opu Nakea are native freshwater stream gobies. O'opu nakea is the most common of the five types of o'opu. It grows up to 14 inches long, and is brown and gray with stripes on its fins, back and tail. There used to be millions of o'opu in streams. O'opu were caught and eaten by early Hawaiians. Today o'opu are protected by law.

	Habitat The O'opu are found in streams between the mountain and the sea. Some o'opu only live in clean, undisturbed streams. Some o'opu can live in dirty disturbed water. The o'opu bottom fins when pressed together turns into a sucker. They use their sucker to climb up waterfalls. The streams they live in is mostly located on Kauai, O'ahu, Moloka'i and Hawai'i. O'opu larvae live in the ocean for 4-6 months.

	Life Cycle In the fall when the streams are filled, female and male o'opu go downstream to mate. The females lay eggs near rocks for protection. The eggs stick to the rocks and males fertizlize them by covering the eggs with sperm. The male o'opu guard the eggs until they hatch, which takes about one day. O'opu larvae cannot live in freshwater long, so the larvae floats downstream to the ocean.

When o'opu are born, they have no eyes or mouth. The o'opu larvae float on the ocean currents around the coasts of islands. Many of the o'opu die by drifting too far out or drifting too close to shore, or they are eaten. The grown o'opu, with bodies less than an inch long, swim back to the streams. In the streams they begin to develop beautiful colors, and start to swim on the bottom of the stream. The young fish continue to move upstream where they will become adults.