The surf sardines are a small family, Notocheiridae, of saltwater atheriniform fish found in tropical and temperate seas in the Pacific and Indian Oceans. They are small fish, typically less than 8 cm (3.1 in) in length, with silver stripes and a keel-shaped underside. They form large schools, and are often found in the surf close to the shore, hence their common name. One species is in Notocheirus and five are in Iso, the latter sometimes is separated into family Isonidae.