The surfperches are a family of viviparous ray-finned fishes, the Embiotocidae. Most species are marine, inhabiting coastal waters from Baja California to Alaska, with a few found in Asian Pacific coasts. The only freshwater species, the tule perch (Hysterocarpus traski), is endemic to California, United States.

From Greek embios meaning 'persistent' and tokos meaning 'birth', alluding to the viviparous reproduction exhibited by embiotocids.

Fossil embiotocids have been found in California, including Eriquius plectrodes from the Late Miocene and the much younger Damalichthys saratogensis.

Surfperches are characterized by deep, laterally compressed bodies and a scaled ridge along the base of the dorsal fin.

Surfperches are viviparous, an uncommon trait among marine fishes. Eggs are internally fertilized, and females carry developing embryos for several months. Embryos develop inside the ovary and absorb nutrients and oxygen directly from the mother’s blood supply, and is additionally nourished by the yolk. Females give live birth to fully formed young instead of laying eggs.

Most births occur in May or June, coinciding with periods of high food availability. Males often become sexually mature within a few months after birth and establish temporary territories during breeding.

The number of offspring increases with female size and varies by population. For example, tule perch in the Russian River produce 12–45 young, while those in Clear Lake produce 25–60 young, reflecting local environmental adaptations.

Many species migrate seasonally—moving to deeper ocean waters in winter and returning to bays or estuaries in spring to give birth.