Migratory; upstream Mekong. Its numbers have declined in the Khone Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also collected from Tha Ngon in the Mekong basin (Ref. 4792). There is a recent decline in abundance; caught with "bet ken" (large hooks) set in isolated "gohk goom" (Crateva nurvala, Capparidaceae trees) (Ref. 9497). In Southern Laos, this fish used to be relatively abundant; big fish are now rare. Many young fish of about 40 g were observed in November-December 1993 as well as in other months. Large fish with eggs were found in June-July and may spawn in Boong Pba Leum, where large fish have been seen surfacing in June and July (Ref. 12369). Also previously caught with hooks in Hoo Sadam, but they are now seldom seen or caught there (Ref. 12369). Also Ref. 2686, 30857, 43281, 56905.