Scientists said a 300-kilogram stingray has been used by a fisherman on the Mekong river in Cambodia.
The giant freshwater stingray, which measured four meters (13 feet) from snout to tail, was discovered last week and returned to the wild after being fitted with a tag to keep track of its behavior.
The monstrous bottom-dweller beat the previous record for the largest recorded freshwater fish, held by a 293-kilogram (646-pound) Mekong giant catfish caught in Thailand in 2005, according to the US-funded Wonders of the Mekong research project.
Experts claim that the stingray, caught in the province of Stung Treng in northern Cambodia, was more than twice the weight of a traditional lowland gorilla.
"In 20 years of research for giant fish on six continents, this is the largest freshwater fish we''ve ever encountered or that''s been documented anywhere in the world," said Zeb Hogan, a fish biologist leading the Wonders of the Mekong project.
"This is an absolutely astounding discovery that is a real asset and is a solid basis for efforts to better understand the mysteries surrounding this species and the incredible stretch of river where it lives."
To learn more about the secretive creature''s elusive behavior, researchers included an acoustic tag to the stingray before returning it to the river.
A fisherman hooked an endangered giant freshwater stingray four meters long and weighing 180 kg last month.
The Mekong is home to more than 1,000 fish species, and the stingray is not the only gigantic lurking in the muddy waters the giant catfish and giant barb also reach up to three meters long and 270 kg in weight.
The megafish is "boramy."
Even in the deepest areas of the Mekong, plastic waste has posed risks to wildlife, as well as "ghost nets," which have been abandoned by fishermen, but are still capable to snare fish.
The famous waterway begins in China and travels south through areas of Thailand, Laos, Myanmar, Cambodia, and Vietnam, feeding 60 million people through its basin and tributaries.
Environmentalists have long expressed concern about a dam construction along the Mekong River that would devastate fish stocks.