Silversides are members of the Atherinidae family and occur throughout the world. They are important forage for larger predators along shores, in bays, and in estuaries.
Every silverside lacks a lateral line and has small, almost useless teeth. Its pelvic fins are located well behind the pectoral fins, and the small, spiny dorsal is well separated from the soft dorsal. The body is typically elongated.
Some silversides live in freshwater; others are marine, found near shore. They are often called shiners but are more commonly referred to as "smelt", although they are not related to the true osmerid smelt.
One of the most prominent silversides is the California grunion (Leuresthes tenuis), which grows to 7.5 inches and is famous for moonlight spawning runs and remarkable beach spawning. A similar fish is the gulf grunion (L. sardina), which is restricted to the Gulf of California.
Also prominent and frequently caught along Pacific piers is the larger (to 17.5 inches) jacksmelt (Atherinopsis californiensis), which has small, unforked teeth in bands. This characteristic differentiates the jacksmelt from the California
grunion and also from the topsmelt (Atherinops affinis), which grows to 12 inches but generally occupies the same range as the jacksmelt.
The topsmelt is most easily distinguished from the jacksmelt by its forked teeth set in a single row, rather than in bands. These species constitute a sizable portion of the Pacific coast "smelt" catch.
Along the Atlantic coast, the tidewater silverside (Menidia beryllina), which grows to only 3 inches long, ranges from Massachusetts to the Gulf of Mexico. Frequently called whitebait and spearing, it is predominantly a saltwater species but is also found in brackish water and freshwater. Several similar species occur in the same general range, including the Atlantic silverside (M. menidia) and the Mississippi silverside (M. audens), a freshwater species.
