Citico Darter (Etheostoma sitkuense)

Description: 

The Citico Darter is a federally endangered species which is currently restricted to a single river system near the Great Smoky Mountains National Park in Tennessee. They live near the banks of creeks primarily in pools with gravel substrate. Like other members of the subgenus Catonotus, this species spawns on the underside of flat rocks. In this group, males of some species have knobs on their first dorsal fin that are hypothesized to serve as an “egg-mimic” to attract females for spawning.