Idaho AFS Logo

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)

Brown bullhead (Ameiurus nebulosus)

Non-native

Brown bullheads are the larger of the "bullhead species" in Idaho. They are typically 9-11 inches, but can grow to 20 inches. Brown bullheads can be found in many lakes, ponds, and slow moving rivers throughout Idaho. They are native to central and eastern North America, where they are very popular gamefish. Brown bullheads can be distinguished from black bullheads by the presence of small, jagged barbs on the trailing edge of the pectoral spine. Equipped with an excellent sense of smell brown bullheads are nocturnal bottom feeders. They are commonly caught by anglers fishing with bait late in the spring during spawning season, or after dark. Interestingly, they are not particularly popular gamefish in Idaho, despite an abundance of healthy populations with large fish. Brown bullheads are extremely hearty fish, tolerant of very low oxygen levels and high water temperatures. For this reason, it is very difficult to eradicate undesirable populations.

Click thumbnails to enlarge