The Hawaiian freshwater goby, Lentipes concolor (‘o‘opu ‘alamo‘o or ‘o‘opu hi‘u koleis), is a species of goby endemic to Hawaii, where it occurs in mountain streams. Males of this species can reach a standard length of 7 cm (2.8 in), while females only reach 6 cm (2.4 in). This species has a salmon-like lifestyle, spawning in fresh water and going out to sea to mature. L. concolor is notable for its unique method of returning to the spawning beds; they use suction disks on their ventral sides to climb the wet rocks behind waterfalls, even scaling the 422-ft-high Akaka Falls.