As far as I know, they are only found in the Northeast. The round goby was discovered in the St. Clair River and comes from the same area of the world as the zebra mussel...around the Black and Caspian Seas. Unless they have entered the watersheds such as the Mississippi River drainage system, they are still limited to the Great Lakes. They do look a lot like sculpins, however, I'm not sure if those are in the Tennessee River or not. Tie one on and give it a try