The plains killifish, Fundulus zebrinus, is not native to Utah, but it has become established in several areas of the Colorado River drainage, in eastern Utah. The species also currently occurs in Juab and Millard Counties, in central and western Utah. The plains killifish naturally occurs east of the Rocky Mountains, from Montana to Texas.
The plains killifish is a small fish, with adults usually three inches in length or smaller. Most plains killifish individuals do not live longer than two years. The species feeds at the surface, eating primarily insects, insect larvae, and other aquatic invertebrates. Spawning occurs during the summer. The plains killifish may negatively impact native fish species, such as the least chub, so it should not be introduced to waters where sensitive native fish species occur.