Etheostoma akatulo, Layman & Mayden, 2009
http://en.wikipedia.org/wiki/Etheostoma_akatulo
> Perciformes > Percidae
Etheostoma akatulo or the bluemask darter is one of the 324 fish species found in Tennessee. It is a federally listed endangered species of the United States. This fish was not formally described until 2009, but it was added to the US Endangered Species List in 1993.
During breeding, the male has bright blue patches on its head and other areas.

This fish is found only in the Caney Fork River system, a tributary of the Cumberland River in Tennessee.
The species name akatulo comes from the Cherokee for "mask", referring to the solid blue coloration on the lower face of the fish.