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

Gravel Chub Erimystax x-punctatus

Cyprinidae (Minnows)
Trophic Class
Benthic Invertivore
Is Exotic to Iowa?
Is Lithophilous Spawner?
Is Hybrid?
State Listing Status
Not Listed
Assessment Program Statistics

This species was found at 10 bioassessment sites, 0 rapid fish bioassessment sites, 7 fisheries assessment sites, and 0 fisheries presence-only assessment sites. In total, it was collected at 17 distinct sites, or 1.3% of the 1285 total sites monitored by the bioassessment program. It is the 88th most commonly collected species.

The Gravel Chub was collected in 15 bioassessment sampling sessions and 7 fisheries assessment sessions. It was present in 0 rapid bioassessment sessions and 0 presence-only sessions.

The biological assessment program has collected a total of 145 individual Gravel Chub specimens, ranking it the #88 most collected fish.

Species Characteristics

The body is light olive-green above with silvery sides and a light blue lateral band. Its most distinctive feature is the presence of scattered "x" or "y-shaped" dark markings on its sides and back. The small, subterminal mouth is horizontal, and a barbel is present at the end of the maxillary. The eye looks large compared to the head. A complete lateral line has 38 to 43 scales. The dorsal and pelvic fin ray counts are 8 in each, while the pectoral fins vary from 13 to 16 rays, and the anal fin has 7 rays. Strongly hooked pharyngeal teeth are arranged on slender arches in a 4-4 formula. A black or dark mottled peritoneum surrounds the stomach cavity, which has a looped gut.

Species Distribution Map