The territorial males spawn over the top of buried females in the gravels of fast-flowing riffle areas.

The Barren River is north of the Nashville Basin, in Clay, Macon, and Sumner Counties, draining the northward-sloping portion of the Highland Rim.

"A typical Highland Rim stream is cool, clear water, gravel substrates, and riffle pool habitats.

"[5][4] The upper Green River system was studied, and six endemic darter species were analyzed.

"Orangefin darter was detected at 46% of the sample sites and occupies portions of all major river systems in the watershed.

Intraspecific competition occurs because small invertebrates are more abundant during different times of the year, and breeding areas become a challenge, also.

The building of dams can slow the flow of water, which will have a major effect on the orangefin because they use rocky substrates and swift-moving riffles for hiding and feeding.

Their ecosystem must stay balanced in the future, or stress on these endemic species can cause extinction sooner.

[6] N. bellus is a moderate-sized darter of the subgenus Nothonotus, endemic to the Green and Barren River system in south-central Kentucky and north-central Tennessee.