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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.

Catfishes (Ictalurids)

Tadpole madtom (Notorus gyrinus)


Generally less than 3-4 inches long, tadpole madtoms are the smallest catfish family member found in Idaho. They are native to eastern and central North America, but can be found in Idaho in the lower Boise River as well as the middle Snake River. They were most likely inadvertently introduced into Idaho when bullheads or channel catfish were introduced over 50 years ago. Tadpole madtoms can inflict a mildly poisonous (but quite painful) wound with the spine on their pectoral fin.

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