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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.

(Salmonoids)

Lake trout (Salvelinus namaycush)

Non-native

Lake trout are another introduced member of the char group. They are similar to bull trout in that they are aggressive piscivores (fish-eaters) that can grow to large sizes. The record in Idaho is 57 1/2 pounds. Lake trout are slow growing, long-lived species that may not mature for 10 years, and can live more than 30 years. Unlike most trout and char in Idaho, which require streams and rivers for spawning and early rearing, lake trout generally carry out their entire life cycle in a lake. For this reason, they have successfully been able to outcompete native species such as cutthroat and bull trout, which have limited habitat to utilize. Unlike most trout and char in Idaho, which require streams and rivers for spawning and early rearing, lake trout generally carry out their entire life cycle in a lake. For this reason, they have successfully been able to outcompete native species such as cutthroat and bull trout, which have limited habitat to utilize.

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