Hawaii has five species of O'opus that are often referred to as gobies. Four of the five o'opus are endemic (found nowhere else on earth) to Hawaii. Their distribution along the stream is believed to be influenced by their climbing ability. The Hawaiians prized the gobies as a food source. During the ancient Hawaiian days, the gobies flourished in fishponds such as Kaelepulu Pond. The pond was known for its supply of freshwater. The o'opu's life cycle is unique because it includes two migrations; one upstream to the freshwater and one downstream to the sea. Their life cycle and stresses the importance of maintaining the "mauka (mountain) to makai (ocean)" connection.

STAGE 1 During the fall rainy season, the female and male o'opu go downstream to mate. The female lays a set of yellow eggs on a rock in the stream. The male fertilizes them. Either the male or the female stays behind and guards them until they hatch. It takes about 24 hours until they finally hatch.

 STAGE 2 When the eggs hatch, they become larvae. They must go downstream immediately or they die.

STAGE 3 When they reached the sea, they join up with other tiny animals and plants such as the plankton, which is an important food source in the ocean for the baby gobies and other sea animals

STAGE 4 The o'opu larvae are carried away by the currents. During this stage, many larvae have died trying to go upstream to grow into adults. The suction cups on the gobie's belly helps them to swim upstream. By clinging to the rocks with their suckers, it helps them to hold their position during a storm.

STAGE 5 The larvae becomes an adult, and this is when the Hawaiians catch them in enormous amounts.