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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.


Cutthroat trout (Oncorhynchus clarkii)


The Idaho State Fish, the cutthroat trout is a symbol of the pristine lakes, rivers, and streams of the west. As the name suggests, cutthroat are easily recognized by the distinct red slashes beneath their lower jaw. Because they evolved in fairly unproductive environments, cutthroat trout have developed the unique adaptation of being exceptionally aggressive and opportunistic feeders-a characteristic that makes them very popular with anglers. Because cutthroat trout require cold water, clean gravel substrate, diverse stream habitat and ample cover, cutthroat are sensitive to habitat changes. There are 3 subspecies of cutthroat trout in Idaho: Bonneville (including Bear Lake variation), Westslope and Yellowstone (including Snake River fine spotted variation).

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