[4] The male plains topminnow's fins are iridescent and have a red tip with blue-purple bands, as well as a gold stripe on the body.

[4] There are no black bars on the fish's body, which makes it distinguishable from the banded killifish, a more common species, which is often found in the same habitats as the plains topminnow.

[3][5] Two other distinct features of the plains topminnow are its rounded caudal fin and the absence of an externally visible lateral line.

The first population of Plains topminnows is largely in Nebraska extending into Iowa, southwestern Minnesota, northeastern Colorado and southern South Dakota.

[8] The plains topminnow breeding season was observed at 60 days in Missouri and Nebraska, regardless of latitude and water temperature.

[4] Breeding behavior for the plains topminnow, demonstrated in wild individuals transplanted into an aquarium, includes direct male competition.

[6] In Minnesota, the plains topminnow is present in all historical locations, however, abundance is lower than normal at 69.2% compared to past collections.

[6] The primary threats to the plains topminnow are physical or chemical habitat degradation, stream fragmentation, introduction of nonnative fishes, reservoir creations, sewage discharge, feedlot runoff, intense livestock grazing and pumping of saline groundwater.

[4] It is also believed that eutrophication, causing low oxygen conditions and high ammonia concentrations, is adding to the depletion of plains topminnow levels.