Video: Cambodia Anglers Catch Biggest Freshwater Fish of All Time

On June 13, Cambodian fisherman Moul Thun accidentally hooked into the largest freshwater fish ever caught and recorded. The giant freshwater stingray (Urogymnus polylepis) is an elusive species that scientists don’t know much about. That’s exactly why Dr. Zeb Hogan and the Wonders of the Mekong research team are studying this and many more freshwater megafauna species that inhabit the mighty Mekong River.

Researchers were in the area installing underwater receivers to track migratory fish in the river when Thun hooked into the monster stingray. The team had been in communication with local fishermen in case such an instance occurred and got on location to weigh the fish.

The massive ray weighed in at 661 pounds and measured 13 feet from snout to tail. There are reports of the ancient fish reaching up to 16.5 feet long and weighing in over 1,300 pounds, but these claims haven’t been verified. Anglers accidentally hooking into these giant fish have capsized boats from their strong pull. Although these behemoths of the deep don’t typically pose much of a danger to humans, they are equipped with a venomous barb on the end of their tail. Like a broadhead, the barb can easily penetrate skin and even bone, introducing a toxin into the fresh wound. This particular specimen, however, had broken its barb off.

Researchers safely tagged and released the enormous stingray, hoping to capture data and gain knowledge on a species and ecosystem that has eluded scientific study for quite some time. This year alone, Dr. Hogan and his research team have weighed and released two giant stingrays weighing over 400 pounds, also caught nearby. The previous title holder for largest freshwater fish ever caught, set in 2005, also came out of a Mekong River—a giant catfish caught in Thailand that weighed in at 646 pounds.

Dr. Hogan has pursued the world’s largest freshwater fish for almost two decades now. His studies have led him to the Mekong, where deep troughs hold some of the world’s largest freshwater species.

“In 2020, one of the contenders for the world’s largest freshwater fish, known as the Chinese paddlefish, was declared extinct,” Dr. Hogan said. “That was very sad news, and it had me feeling like we were going to see more extinctions of these big fish, rather than records being broken.”

Although the giant freshwater stingray is listed as endangered on the IUCN Red List of Threatened Species, it's not illegal to fish for them in Cambodia. They aren’t considered great table fare however, so fishermen don’t often target them. As bottom-dwelling creatures that feed on shrimp, mollusk, and small fish, they are often by-catch of nets or deep water hooks.

“The fact that the world’s largest freshwater fish was caught in the Mekong is remarkable,” Dr. Hogan said. “This is a heavily populated region, and the river faces a ton of challenges.”

One of the most notable challenges is the construction of “megadams.” The massive structures keep big fish from moving through the river and spawning, despite the presence of aids like fish ladders. Additionally, the giant dams also promise to uproot small villages, bottleneck food supplies in the area, and increase the dramatic impacts of flood and drought seasons.

The Cambodian government recently agreed to the construction of a 1,400-megawatt hydropower dam on the Mekong just north of Stung Treng. “It will mean the loss of fisheries, loss of biodiversity, loss of livelihoods,” Dr. Hogan said. “It will alter this area forever.”

Thun caught this particularly impressive specimen in a deep area of the Mekong, where pools can get up to 90 meters deep. The river is one of the few habitats in the world that can sustain freshwater megafauna of this caliber, but it’s unknown how long it will be able to do so with overfishing, pollution, and dam construction.

"Big fish globally are endangered. They're high-value species. They take a long time to mature. So if they're fished before they mature, they don't have a chance to reproduce," Dr. Hogan said. "A lot of these big fish are migratory, so they need large areas to survive.”


Kalon O Blackout Spinning Reel
Save this product
13 Fishing
At home both in open water and in the frozen tundra, 13 Fishing Kalon O Spinning Reels are performance-proven and tested by the most rugged and rowdy anglers we know.
MeatEater Branded Yeti Hopper M30
Save this product
Whether you're into suds, brewskis, seltzers, or vino, if it comes in a can or bottle and is best served cold, the Hopper M30 is the ticket.
Mermaid's Trident Zesty Seafood Blend
Save this product
A bright citrus-based blend that is balanced with earthy notes of smokey chardonnay and mild heat to round it out. This unique combination is incredibly versatile, perfectly pairs with your latest catch, fresh garden veggies, or atop roasted potatoes.
Inception Baitcast Reel
Save this product
13 Fishing
A lightweight body and super low-profile design provide incredible comfort during long days on the water.
Omen Black Spinning Rod
Save this product
13 Fishing
Japanese 36 Ton Toray Graphite , 4A Portuguese Cork Handle, ALPS 316 Stainless Steel Guides with Zirconia Inserts.
LoadOut GoBox 30
Save this product
The MeatEater crew uses our GoBoxes for storing all kinds of gear, from ammo and range hardware to outdoor kitchen essentials, dog accessories, fishing tackle, and gear, camera equipment, truck tools, and medical supplies. Why buy expensive hunting and outdoor gear only to store it in a cheap plastic bin with a lid that doesn't fit correctly? Elevate your gear protection and organization with this waterproof, dustproof, shockproof, and critter...
Get the latest in your inbox
Subscribe to our newsletters to receive regular emails with hand-picked content, gear recommendations, and special deals.
Our picks for the week's best content and gear
For the whitetail obsessed, with Mark Kenyon
Redefining our connection to food, with Danielle Prewett
Your one-stop for everything waterfowl, with Sean Weaver
Get out on the water with the MeatEater Fishing crew
Technical hunting apparel
Purpose-built accessories for hunting and fishing
Quality elk, turkey, waterfowl, and deer calls
Save this article