Iowa DNR
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Rainbow Trout Oncorhynchus mykiss

Salmonidae (Trouts)
Trophic Class
Top Carnivore
Is Exotic to Iowa?
Is Lithophilous Spawner?
Is Hybrid?
State Listing Status
Not Listed
Assessment Program Statistics

This species was found at 30 bioassessment sites, 0 rapid fish bioassessment sites, 47 fisheries assessment sites, and 1 fisheries presence-only assessment site. In total, it was collected at 76 distinct sites, or 5.9% of the 1294 total sites monitored by the bioassessment program. It is the 55th most commonly collected species.

The Rainbow Trout was collected in 63 bioassessment sampling sessions and 127 fisheries assessment sessions. It was present in 0 rapid bioassessment sessions and 1 presence-only session.

The biological assessment program has collected a total of 1,268 individual Rainbow Trout specimens, ranking it the #60 most collected fish.

Species Characteristics

Olive to greenish-blue over most of the upper body, fading to a silvery-white along the belly. They are most easily separated from the other trout species by the strikingly prominent pink-red horizontal stripe that extends down each side of the fish. The sides, back, dorsal and caudal fins have small black spots continuing to the distal end of the caudal fin. Like most trout, there are sharp teeth on the vomer in the roof of the mouth. Scale counts along the lateral line range from 135 to 155.

Species Distribution Map