Asia: Indus, Ganges-Brahmaputra, Mahanadi, Krishna, Cauvery, and other river basins in southern India; Irrawaddy, and Salween; Meklong, Chao Phraya, Mekong and virtually all coastal river basins of peninsular Thailand and Malaysia; Sumatra and Java. Has never been reported in Borneo and is not present in the Red River basin of Tonkin (North Viet Nam).