Forage Fish
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Closeup photo of Longfin Smelt with descriptions of identifying anatomy.
Photo: Several Longfin Smelt of various ages in a tray. Photo: A large pile of Longfin Smelt
Photo: A young Longfin Smelt being held in the water.

Forage Fish Identification Guide

Longfin Smelt
Spirinchus thaleichthys

Occasionally caught with dip nets during winter spawning migrations to the lower Nooksack River.  A land-locked freshwater population resides in Lake Washington.

Description: Longfin Smelt are silver with pale olive brown to pink shades alone the spine.  The body is small and elongate with an incomplete lateral line that reaches just to the dorsal fin.  They have distinctive long pectoral fins that reach nearly to the base of the pelvic fins (inspiring the common name).    Their anal fin is both longer and broader than that of Whitebait and Night smelts.  They have a long upper jaw which almost reaches to the posterior edge of the eye, and the lower jaw projects slightly in front of the upper jaw.  There are fine teeth in a single row on both jaws.

Maximum Size: To 20 cm (8 in) in length.

Maximum Age: 3 years.

Range/Habitat: Longfin Smelt are found from the Shelikof Strait in the western Gulf of Alaska to Monterey Bay, California.  They are found in the surf and from the surface to depths of approximately 137 m (449 ft).   They are an anadromous fish that spawns in freshwater and then most die.  Longfin Smelt feed both in the water column and on the bottom, on amphipods, euphausiids, mysid shrimps, copepods, cumaceans, and insects. They are prey to Chinook salmon, cutthroat trout, striped bass, spiny dogfish, murres, seals, and porpoises. 

Additional Information


  • Love, M.S., 2011. Certainly More Than You Want to Know About The Fishes of The Pacific Coast: A Postmodern Experience. Really Big Press, Santa Barbara, California, 650 p.
  • Penttila, D. 2007.  Marine Forage Fishes in Puget Sound.  Puget Sound Nearshore Partnership Report No. 2007-03.  Published by Seattle District, U.W. Army Corps of Engineers, Seattle, Washington.
  • Longfin Smelt Wiki
  • FishBase.Org

Photo: S. Freitas, L. Lloyd and T. Cornwell