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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.


Arctic grayling (Thymallus arcticus)


Arctic grayling have a holarctic distribution, that is they are found around the earth at arctic latitudes. Grayling naturally inhabit both lakes and streams. They are not native to Idaho, but have been introduced to provide fishing opportunities in some alpine lakes. Grayling spawn in the spring with adults typically reaching 10-15 inches in length and can live as long as 11 or 12 years. They have sail-like, colorful dorsal fins are well noted for their eagerness to take a fly.


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