Like most darters, the Niangua darter is slender, having a long, thin body. However, it is rather large for a darter, averaging three to four inches from head to tail. The body is yellowish-olive and has eight dark bars across the back. Healthy specimens display orange spots scattered over their upper sides in addition. Also, a series of U-shaped greenish blotches alternate along its side with thin, narrow, orange markings (Missouri Department of Conservation).The Niangua darter can be distinguished from other darters by the presence of two small, black spots at the base of its tail fin. Without these spots, the Niangua darter is nearly identical to many other darters. This is because the coloration displayed by the Niangua darter is quite comparable to that of other darters. However, these identifying spots are not apparent in breeding males. This can be attributed to the spawning behavior that they exhibit, clearing possible spawning areas with its tail. During this process, the scales along the bottom side of the tale, including the dots, simply wear off. They do, however, grow back and reappear at the end of the breeding season. The Niangua darters closest known relative is the arrow darter, which can be found in eastern Kentucky and northern Tennessee. Not surprisingly, it lacks the distinctive black tail spots of the Niangua (Missouri Department of Conservation). The two species never cross paths during their lifetimes, and therefore there is no confusion in identifying between the two very similar-looking species.Darters are an important part of any stream ecosystem. They generally play the crucial role of secondary consumers, comprising most of their diet of soft-bodied animals that feed mainly on photosynthetic organisms. With its slender snout, the Niangua darter probes crevices in rock and gravel for aquatic insect larvae, crustaceans and snails (USFWS). Also, it is known to predate upon the nymphs of stonef...
