Acheilognathus deignani
Acheilognathus deignani is a species of freshwater ray-finned fish in the genus Acheilognathus, a bitterling. It is endemic to northern Vietnam and Mekong River basin. It grows to a maximum length of 5.2 cm.
Named in honor of Herbert Girton Deignan, Associate Curator of Birds, U.S. National Museum, who collected the type specimen.