It`s body is large with flattened side. Its head is rather large. It has small eyes, no teeth, and one short pair of barbel on a nook just above mouth angle. Its body is grey-red at the back and becomes grey-blue at the side and white at the bottom of belly. There is one black dot opposite to the end of pectoral fin and 3 black dots on caudal fin. Every fins have light grey in color.
It is found only in Klong River and its river branches. It used to be found in Chan region of Burma and Yunan Region of South China. It likes to dwell in deep water; this comes to a depth of more than 10 meters. The water ground should fill with pebbles and have underwater rock shed and cave.
It eats seaweed growing on underwater rock.
It is patient and easily frightened. It likes to stay as a group in the deep running water areas. Mekong Giant Catfish will swim upstream to lay eggs toward the north from Thailand at Luang Prabang in Loas. It is a suitable area for breeding and spawning during dry season as it is the deep water area with lots of islets. During flood season, Mekong Giant Catfish will swim downstream to the lower part of Klong River.
At the present, The Thai Department of Fisheries has successfully inseminated Mekong Giant Catfish since 1983. Later year, Thailand fertilized a large numbers of Mekong Giant Catfish and distributed to water resources all over Thailand. Those Mekong Giant Catfish grew quickly, but it was uncertain whether they could breed and spawned. There is a catching Mekong Giant Catfish festival every year at Chiang Klong District, Chiang Rai province. During the festival, lots of mature Mekong Giant Catfish are caught, which make a number of Mekong Giant Catfish decrease significantly.
It is believed that its breeding season is around February.
It is a large freshwater fish having no scales. Its body length is nearly 3 meters and weighting is more than 250 kilograms.