Also called the Mekong giant catfish, the Thailand giant catfish is found in the Mekong basin of Thailand. It is said to be the most vulnerable freshwater species, and according to the Guinness Book of Records, it is the largest freshwater fish in the world. Adults can reach over 9.8 feet in length and can weigh over 650 lb. The species also has one of the fastest growth rates of any fish in the world and can reach up to 400 lb by its sixth year. The skin of the giant catfish is gray to white in color with no stripes, and this fish is distinguished from other large catfish in the Mekong by its lack of teeth and the almost complete absence of barbels.
The Thailand giant catfish is a migratory species and can only thrive in fresh water. Each year from October to December, this fish moves out of the Tonle Sap Lake in Cambodia into the mainstream of the Mekong River. From there, it is believed to migrate upstream into northeastern Cambodia and possibly Laos, or Thailand to spawn. Diet is unconfirmed but said to consist of other fish and even mammals such as goats. Little is known about its reproductive behavior.
The Thailand giant catfish was once abundant in the 1900s, but in the 1970s local fisheries began to report the disappearance of the species. Research has indicated that the species population has fallen by 80% in the last 13 years. This species is now listed as critically endangered due to overfishing and habitat loss and degradation. The quality of the water in the Mekong basin has been reduced due to development and upstream damming. Fishing has been banned in Thailand, Laos, and Cambodia but the ban has helped little.