Blackthroat Threefin

One of the most commonly encountered small fishes in rocky environments, the Blackthroat Threefin can be difficult to identify because its appearance rarely matches its common name. The males of this species are readily identifiable from their greenish body and black underside, but females can be either reddish or greenish, with white blotches along their back and a dark patch under the eye. They can be mistaken for their relatives in the genus Trinorfolkia, from which they differ due to the lack of a distinct diagonal stripe under the eye. They can also be confused with the Dragonet (Bovichtus angustifrons), which have a more obvious red and white striped colouration and a white head, and prefer vertical surfaces such as rock walls and jetty pylons, while H. decurrens is usually found on horizontal rock surfaces.