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Fishes of Idaho

How are your identification skills? Do you know which are native and which were introduced? To see photos and descriptions, and learn more about Idaho fish, check out our Fishes of Idaho online database.

There are around 20,000 species of fish in the world. About 58% of these are marine (saltwater) fish, 41% are freshwater fish, and 1% are both. We have around 100 species in Idaho, and the list keeps growing as more non-native fish are released into Idaho waters. There are only 39 species of fish native to Idaho. The rest were introduced--some by accident, but most on purpose.

Minnows (Cyprinids)

Northern pikeminnow (Ptychocheilus oregonensis)


The northern pikeminnow is native to the pacific slope of western North America from Oregon north into British Columbia. In Idaho, the species is found in lakes and streams of the Snake River below Shoshone Falls, and the Spokane, Pend Oreille, and Kootenai River systems. It prefers lakes and slow moving portions of streams. They spawn in late spring/early summer in shallow water over a gravelly bottom in streams, but will spawn along lake shores. Eggs apparently are randomly deposited over gravel beds. Females produce from 12,000 to 100,00 eggs, depending on size (average about 40,000). Size of mature fish usually varies from 2 to 5 pounds, but they have been reported to 29 pounds and 25 inches in length. Juveniles feed on a variety of aquatic invertebrates, but fish are the favored prey of larger fish. In addition to young salmon and trout, pikeminnows also feed on sculpins, other minnows, and suckers. They are considered serious predators of game fish and much effort has been expended in attempts to eradicate them. Currently there is a bounty program on them if caught from the lower Snake River in Washington.

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