A species of freshwater fish in the shark catfish family and one of the largest freshwater fish species in the world. Fishing of this species used to be accompanied by religious ceremonies and rites. It is often mentioned in textbooks, news media, and popular press. It has declined drastically mainly due to overfishing and it is now considered Critically Endangered. This species is likely to have been affected by the destruction of rapids and reefs as part of the Upper Mekong Navigation Improvement Project, and by the construction of dams. Projects such as these affect the natural flood/drought cycles throughout the river, and therefore their migratory behavior.