Squalidus maii is a species of freshwater ray-finned fish belonging to the family Gobionidae, the gudgeons.

The fish was discovered in 1997 and named in honor of Mai Dinh Yen (b.

1933),[3] Professor of Hanoi Science University and freshwater fish taxonomist.

[4][5] The original fish were found in a small river stream, about 25m wide and 50-100cm deep.

"Parasqualidus maii, a new genus and species of cyprinid fish (Teleostei: Cyprinidae) from central Viet Nam" (PDF).