Nothonotus is a genus or subgenus of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches.

[7] Frequent hybridization, the rich diversity of the subgenus, and the limitations of the fossil record complicate phylogenetic assessments, which have not been fully resolved.

[20] The following Nothonotus species have been designated conservation statuses by IUCN redlist: Vulnerable : N. maculatum, N. acuticeps, N. denoncourti, N. etowahae, N. wapiti; Near threatened: N. aquali, N. tippecanoe; Endangered: N. moorei, N.

[21] Impoundment by dams and siltation restrict gene flow between previously continuous populations, threatening the genetic diversity of various Nothonotus species.

[23] Sediment issues occur when anthropogenic activities like mining, deforestation, urbanization, and road construction alter flow regimes and erosion rates.