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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.

Minnows (Cyprinids)

Goldfish (Carassius auratus)


The goldfish is a minnow native to eastern Asia, but widely introduced throughout the world and the U.S. U.S. Fish Commission personnel first introduced it into Idaho in the late 1880's. There are scattered populations in several areas of Idaho. They inhabit still waters, often low in oxygen, with thick vegetation. Goldfish are omnivores, feeding on plant material and a variety of aquatic invertebrates. Adults in Idaho probably deposit from 200 to 2000 adhesive eggs in late spring to mid-summer over submerged vegetation. Although this species reaches 18 inches in length and 3 pounds in some places in the world, most Idaho specimens are less than 8 inches in length. Introductions have occurred by the U.S. Fish Commission, by escapes from hatcheries and outdoor ponds, and by releases of aquarium fish and unused bait. These introductions have been detrimental to native fishes in most cases, although in Idaho, this species has not increased in numbers to become a nuisance.

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