Uhu can be tricky to identify because they undergo life phases, changing colors and patterns in each phase. In general, they begin life as females, but once reproductively mature, they are capable of becoming male if the need arises. Males are larger and more brilliantly colored (often with blues and greens) than the females, (typically a drabber red and brown), and patrol territories that include a group of females, which is referred to as a harem. The large size of the male and the tastiness of the parrotfish in general, is cause for some concern about fishing pressure on uhu, and how to best manage their populations.
The uhu in Hawaiian waters include the three endemic species: the Yellowbar Parrotfish, Regal Parrotfish, and the Spectacled Parrotfish. Other species include the Stareye, the Bullethead, the Redlip, and Palenose Parrotfish.