Surf smelt are small marine fish native to the north Pacific. Their range begins in southern Alaska and extends down the coast of North America to southern California. Surf smelt often live quite close to shore, especially as juveniles. A schooling fish, they are found in many coastal estuaries along the Pacific coast, spawning in water as shallow as half a metre, usually on coarse sand or fine gravel beaches.

Surf smelt are small, silvery fish with a streamlined body. They have two dorsal fins, the first of which is flat and about midway down their length. The second is very small and close to their tail fin, which is strongly forked. Males and females differ in their colouration, with males having a brown back and yellowish underside and females a bright green back and white underside. Males are also distinguished by the tubercles on their flanks. Both sexes have a dark line that runs down their sides. Surf smelt can grow to about 20 centimetres in length.