The study on biological characteristics of grey eel catfish (Plotosus canius) distributed in Hau River was carried out from April, 2007 to May, 2011. Specimens (n=1,692) were collected monthly at five sampling sites including Long Xuyen city (An Giang province), Thot Not, Ninh Kieu (Can Tho city), Đai Ngai and Tran De (Soc Trang province). The samples were kept alive or in cold conditions, and transported to the lab of College of Aquaculture and Fisheries, Cantho University for analysis. The result show that P. canius are distributed at all five sampling sites belong to Hau River in freshwater areas such as Long Xuyen, Thot Not, Can Tho, and in brackish water areas as Đai Ngai, Tran Đe. The large specimens were collected in the main Hau River, while the small fish (fry) were caught from the main, the first and the second branches of the river. Grey eel catfish are only found in the Eros ional riversides where are deep and have foot of trees or rock. P. canius adult can appear in the Vietnamese ? Cambodian border.

Key word: Distribution, Hau River, grey eel catfish, Plotosus canius