The Sacramento blackfish, Orthodon microlepidotus, is a cyprinid fish of central California. It is the sole member of its genus.

Blackfish are distinctive for their overall dark color (thus the common name). Younger individuals are more silvery, but darken as they age. The scales are unusually small, counting 90-114 along the lateral line. The forehead has a straight-line profile, the eyes are smallish, and the terminal mouth slants upwards. The dorsal fin starts just behind the pelvic fins, and has 9-11 rays, while the anal fin has 8-9 rays, and the pelvic fins 10 rays. The pharyngeal teeth are long, straight, and knife-shaped; the dorsal part of each tooth has a narrow grinding surface. They have been recorded at up to 55 cm in length.