The rush darter is a small fish that grows to two to three inches long.
We do not understand the reasons for decline among many of the darter species.
British Dictionary definitions for darter
Also called anhinga, snakebird. any aquatic bird of the genus Anhinga and family Anhingidae, of tropical and subtropical inland waters, having a long slender neck and bill: order Pelecaniformes (pelicans, cormorants, etc)
any small brightly coloured North American freshwater fish of the genus Etheostoma and related genera: family Percidae (perches)