Giant Catfish May Be World's Largest Freshwater Fish

Fishers in northern Thailand netted this huge catfish in the Mekong River.Nearly nine feet long (2.7 meters) and as big as a grizzly bear, the behemoth tipped the scales at 646 pounds (293 kilograms). Experts say the fish, which belongs to the species known as the Mekong giant catfish, may be the largest freshwater fish ever recorded.

Thai fishers struggled for more than an hour to haul in the record-breaking Mekong giant catfish. Officials from Thailand's Inland Fishery Deparment then used a performance-enhancing drug to stimulate the pituitary gland of the female fish in order to prepare it for a breeding program (above). Despite efforts to keep the bear-size catfish alive, it died and was later eaten by villagers.

The species is listed as critically endangered by the World Conservation Union (IUCN) and faces a high risk of extinction in the wild. The rare specimen, captured in the Mekong River in Chiang Khong district, is the largest since Thailand began keeping records in 1981.

Thai fisheries officials had hoped to release this adult female Mekong giant catfish after they stripped it of eggs (above) for a captive-breeding program. But the whopping fish, which was as big a grizzly bear, didn't survive.

Listed a critically endangered by the World Conservation Union (IUCN), the Mekong giant catfish is one of the world's largest freshwater fishes. Other contenders include the Chinese paddlefish and the dog-eating catfish—another Mekong River giant.


After a record-breaking Mekong giant catfish died, residents of Hat Khrai, a Thai village on the Mekong River, butchered the fish for its meat.

"Mekong people believe it's a sacred fish, because it persists on plant matter and 'meditates'"—in the deep, stony pools of the Mekong River—"somewhat like a Buddhist monk, said Zeb Hogan, a fisheries biologist who studies the largest freshwater fish in the world. A WWF conservation fellow and National Geographic Society Emerging Explorer, Hogan has received funding from the National Geographic Society Conservation Trust.

Mekong giant catfish attract high prices in Thailand, because eating the fish is supposed to bring good luck. Likewise, the Chinese believe that catfish meat boosts intelligence and prolongs life.