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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.

Suckers (Catostomids)

Utah sucker (Catostomous ardens)


The Utah sucker is native to the old Bonneville basin of UT, ID, WY, and NV. In Idaho, the species is found in the Snake River system above Shoshone Falls, the Bear River drainage, and the independent drainages. It is an adaptable species living in lakes, reservoirs, rivers, and creeks with slow to moderate current at a variety of temperatures. They spawn in the spring and females deposit eggs over gravel and sand. Males then stir the substrate with violent movements of their tails, thereby partially burying the eggs. They are bottom feeders, taking both plant material and benthic organisms. They often graze on filamentous algae attached to rocks. This species reaches 15 to 20 inches in length and 4 - 5 pounds or more in some localities. They were used as food by early settlers in the Bear River area, but are seldom used for that purpose today.

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