Emerald Darter (Etheostoma baileyi)

Description: 

Emerald Darters are found in the upper Cumberland and upper Kentucky river drainages. Like many members of the Snubnose Darter group, they have a blunt snout, and they reside in the transition zone from pools to riffles. As the common name suggests, Emerald Darters have emerald squares along their side, which expand into bars in breeding males.