Sole member of its genus. Endemic to central California. Distribution from Wikipedia: "Blackfish are primarily denizens of the warm and cloudy waters found on the floor of the Central Valley, such as sloughs and oxbow lakes connected to the Sacramento and San Joaquin Rivers. They are also common in Clear Lake, Pajaro River, Salinas River, the small creeks that feed into San Francisco Bay. A population is present in the Russian River, believed to have been introduced. They also thrive in reservoirs, and have been spread to a number of California reservoirs via the California Aqueduct, and into Nevada via the Lahontan Reservoir (1964) where they have further colonized the Humboldt River drainage."