The emerald darter (Etheostoma baileyi), a fish species in the family Percidae found only in northern and eastern Kentucky and northeastern Tennessee. E. baileyi is a member of the snubnose darter subgenus (Ulocentra) and shares many similarities with other species in the group, such as eight or nine dorsal saddles, a blunt nose, scales on the belly, and other distinguishing characteristics. Emerald darters are moderate-sized darters, ranging from 2.9 to 5.0 cm. Males are generally slightly larger and are more dramatically colored than females, with green accents on various parts of their bodies. Emerald darters can be found in rocky pools of small to medium creeks and rivers that maintain temperatures ranging from 0 to 25°C. As suggested by the emerald darter’s subterminal mouth, they are