Fishes of Idaho

How are your fish identification skills? Do you know which are native and which were introduced? To learn more about Idaho fish, check out our Fishes of Idaho 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.

Fish	Family	Origin
American shad Alosa sapidissima	Clupeidae	Native
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Arctic grayling Thymallus arcticus	Salmonoids	Non-native
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.
Bear Lake whitefish Prosopium abyssicola	Salmonoids	Native
The Bear Lake whitefish is native only in Bear Lake in Idaho and Utah. These small native whitefish rarely exceed 8 inches in length. They are winter spawners and are difficult to catch with hook and line, but they have a reputation for being good to eat. Some early settlers to the area harvested these fish for commercial purposes, selling them at meat markets.
Bonneville cisco Prosopium gemmiferu	Salmonoids	Native
The Bonneville cisco is native only to Bear Lake in Idaho and Utah. These fish first reproduce at the age of three and a 6 inch female can produce over 2,500 eggs, to be spawned in winter. Bonneville cisco are planktivores, feeding primarily on zooplankton. Like the Bear Lake whitefish the Bonneville cisco is not usually captured with standard fishing gear, but they are reported to be good eating.
Bonneville whitefish Prosopium spilonotus	Salmonoids	Native
The Bonneville whitefish is native only in Bear Lake in Idaho and Utah. Like the Bear lake whitefish, the Bonneville whitefish is relatively small. It rarely exceeds 12 inches in length. Bonneville whitefish spawn in early winter and are vulnerable to angling. Their flesh is reported to be very good to eat.
Brook trout Salvelinus fontinalis	Salmonoids	Non-native
Brook trout were introduced to Idaho in the late 1800's in an attempt to duplicate their popularity in the eastern United States. Like bull trout, brook trout are char and spawn in the fall. The genetic similarities and habitat overlaps of the two species have resulted in unfortunate hybridization between the two species in many areas, further threatening bull trout populations. Brook trout are also a threat to native cutthroat and rainbow trout because of their highly aggressive nature and slightly larger size as fry. Brook trout are moderately popular sport fish in Idaho, although their tendency to mature at small sizes in unproductive waters leads to overpopulation and stunting.
Brown trout Salmo trutta	Salmonoids	Non-native
Brown trout are native to Europe and western Asia. They were introduced to North America as a sportfish in the mid 1800's. Brown trout are aggressive piscivores (fish eaters) that can grow to large sizes--the record in Idaho is 26 pounds, 6 ounces. Brown trout spawn in mid to late fall in rivers and streams, and spend their adult years in habitats ranging from small streams to large lakes. Anadromous (ocean-migrating) populations have developed in many parts of the world. Brown trout are more tolerant of warm water temperatures than Idaho's native trout species.
Bull trout Salvelinus confluentus	Salmonoids	Native
Bull trout are Idaho's only native species of char-a sub-group of the trout and salmon family that is distinguished by light-colored spots and fall spawning. Bull trout are secretive fish that require extensive cover in the form of pools, streamside vegetation and log jams. In addition, they require very cold water. Because of their particular habitat requirements, bull trout are extremely sensitive to habitat degradation. Non-native species, such as lake trout and brook trout BULL TROUTa.jpg (14874 bytes)also threaten bull trout through predation, competition, and hybridization. Overharvest and poaching have contributed to the decline of bull trout populations in Idaho as well. Because of the depressed and declining status of bull trout, they are listed as a threatened species under the Federal Endangered Species Act.