The giant catfish, believed to be the largest freshwater fish ever found, was caught along the Mekong River, home to more species of massive fish than any river on Earth.

"We've now confirmed that this catfish is the current record holder, an astonishing find," Dr Zeb Hogan, a WWF Conservation Science Fellow, said in the joint statement.

Local environmentalists and government officials tried to negotiate the release of the fish so it could continue its spawning migration in the far north of Thailand but the adult male died and was eaten in a remote village, it said.

The Mekong giant catfish is southeast Asia's largest and rarest fish and the focus of a National Geographic Society project headed by Hogan to study freshwater fish greater than 6.5 feet or 220 pounds (100 kg). (