Plains Killifish Identification Guide

Key identification features

• Elongated, slightly rounded body shape
• Dorsal fin set well back toward the tail
• Olive-tan to yellowish base color
• 15 to 20 thin, dark vertical bars running along each side
• Small, upturned mouth for feeding near the surface or substrate
• Maximum size around 4 inches

Common look-alikes

• Banded killifish: shows fewer, less regular bars and occupies a more northeastern range rather than the Great Plains
• Other prairie Fundulus species: closely similar in shape, separated mainly by precise bar count and river drainage
• Sheepshead minnow: much deeper-bodied and restricted to coastal brackish habitats rather than prairie rivers

Where you'll see one

The plains killifish is native to Great Plains river systems, including the Missouri, Platte, and Arkansas River basins. It favors shallow, sandy or silty runs of prairie streams and rivers, and is notably tolerant of high turbidity and the fluctuating flows typical of these open, exposed waterways, often burying itself partly in loose sand when resting or avoiding predators.