The Sacramento Splittail, Pogonichthys macrolepidotus, is a cyprinid

Cyprinid

The family Cyprinidae, from the Ancient Greek kyprînos , consists of the carps, the true minnows, and their relatives . Commonly called the carp family or the minnow family, its members are also known as cyprinids...

 fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 native to the low-elevation waters of the Central Valley in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It was first described by William O. Ayres in 1854. It is the sole living member of its genus, the Clear Lake splittail

Clear Lake splittail

The Clear Lake splittail was endemic to California's Clear Lake and its tributaries until its numbers severely declined due to competition from the introduced bluegill and alterations to the flow of inlet streams...

 P. ciscoides having become extinct in the 1970s.

The distinctive feature of the splittail is the larger upper lobe of the tail fin.