Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Formerly the most abundant of all fish species in the Mekong at Ban Hang Khone. The species has declined steadily since 1970 until now it is relatively rare, no large scale migrations have been observed for about ten years, and is considered by fisherfolk to most likely disappear (Ref. 9497). The most successful fishermen in Ban Hang Khone reported he caught 400-500 kg yearly during the entire January-February migratory period in the 1970s. His catch declined to 20-30 kg over a 10 day-period in February about 10 years ago (1984?) (Ref. 12369). Reported to migrate upstream above the Khone Falls from March to June (Ref. 37770). The combination of the first rain, increased water levels and increased turbidity are the main factors that trigger upstream migration (Ref. 37770). Museum: Mekong below Khone falls, CAS 96773; Mekong at Ban Hang Khone, just below Khone falls, CAS 96873 (Ref. 5515). Also Ref. 188, 12693, 30857, 37772, 44002, 56905.