The Mekong giant catfish (Pangasianodon gigas) it is the world’s largest catfish fish and a candidate for the world’s largest freshwater fish. Reaching three meters (10 feet) in length and weighing almost 650 pounds (295 kilograms), its lives mainly in the lower half of the Mekong River system, in Cambodia, Laos, Thailand, and Vietnam.

The Mekong giant catfish (pla buek) takes between six years and 12 years to reach full size. According to National Geographic: They "have very low-set eyes and are silvery to dark gray on top and whitish to yellow on the bottom. They are toothless herbivores who live off the plants and algae in the river. Juveniles wear the characteristic catfish “whiskers,” called barbels, but these features shrink as they age. Average life span in the wild: More than 60 years. [Source: National Geographic website]

“Highly migratory creatures, giant catfish require large stretches of river for their seasonal journeys and specific environmental conditions in their spawning and breeding areas. They are thought to rear primarily in Cambodia’s Tonle Sap lake and migrate hundreds of miles north to spawning grounds in Thailand. Dams and human encroachment, however, have severely disrupted their lifecycle.

Eleanor J. Sterling and Merry D. Camhi wrote in Natural History magazine, The Mekong giant catfish, is just one of the region’s struggling, overfished residents. With such grand proportions, a jackpot of succulent flesh that once sold at a premium to urban restaurants, the giant catfish was a fisherman’s prize catch. In the mid-twentieth century, hundreds of giant catfish---a naturally rare species---were caught each year, but recently the annual catch has declined to fewer than ten. Overfishing is the main cause of the decline, but habitat fragmentation and alteration of spawning grounds by dams and navigation projects also contribute. Today, the giant catfish is critically endangered, its range is greatly restricted, and the average size of individuals is declining. In recent years, Cambodia, Laos, and Thailand have outlawed catching the giant catfish. But the species is migratory, so a regional agreement may be necessary to prevent its demise. [Source: Eleanor J. Sterling and Merry D. Camhi, Natural History magazine, December 2007]

Catching a Mekong Giant Catfish

In 1969, Thai fishermen near the Burmese border caught 69 giant catfish, In 1998 they caught one. In Thailand it has been several years since one has been caught. In Cambodia only about five fish are caught a year. When one is caught in Cambodia conservationist often rush to the scene and buy it from the fishermen, then weigh and tag the fish and release it. The money the fishermen get is often equal to a decades worth of pay.

The best place to catch pla buek is a stretch of the Mekong between northen Thailand and Laos near the Huay Xai, The fish is caught in April and May when river levels are low and the fish migrate to Lake Tali in Yunnan Province in China to spawn. Local fishermen sacrifice a chicken and spill its blood into the river as an offering to the river spirit who protect the catfish. The fish are caught with special nets strong enough to hold them

The pla buek is regarded as a delicacy in Thailand. The flesh is said to have a taste similar tuna and swordfish A single fish can fetch $5,000 at a market in Bangkok and ate sought after by gastronomes. Fishermen can only take 50 or 60 a year.

Fishermen Catch 293-Kilogram Mekong Catfish and Eat It

The largest freshwater fish ever recorded was a Mekong giant catfish caught in northern Thailand in 2005. It was nearly 2.7 meters (nine feet) long and weighed 293 kilograms (646 pounds). According to news reports: “Thai fishermen caught a 646-pound catfish believed to have been the world's largest freshwater fish ever recorded, a researcher said. The 8.9 foot long Mekong giant catfish was the heaviest recorded fish since Thailand started keeping records in 1981. The villagers had hoped to sell the fish to environmental groups, which planned to release it to spawn upriver, but it died before it could be handed over. The catfish was later sold in pieces to villagers to be eaten.”

Reporting from Hat Khrai, Thailand, Seth Mydans wrote in the International Herald Tribune, “The monster fish announced itself with four resounding whacks of its tail, thrashing against the net that had trapped it in the pale brown water of the Mekong River. It was a fish called the giant catfish and it was the size of a grizzly bear, taking five boatmen an hour to pull it in and 10 men to lift it when they reached the shore in this remote village in northern Thailand. It was only after their catch had been chopped into pieces and sold that they learned how special it was. At 2.7 meters, or 9 feet, long and weighing 293 kilograms, or 646 pounds, it may be the biggest freshwater fish ever recorded. [Source: Seth Mydans, International Herald Tribune, August 25, 2005]

“Before he headed out, one of the fishermen, Thirayuth Panthayom, made sure luck would be on his side. He said he prayed at the shrine to the God of Catfish and begged his boat to help him: "Please, Miss Boat, let me catch something today and I'll sacrifice a chicken for you." He had only been out for 15 minutes when, he said, he saw the fish smack the water four times with its tail - "Pung! Pung! Pung! Pung!" It took his crew an hour to pull it in. His father, as owner of the boat, earned nearly 80,000 baht, or about $2,000, for the fish from the village fishing association, a fortune in rural Thailand. Thirayuth, like each of the other four members of the crew, got 7,000 baht of this, which he said he gave right back to his father.

As part of its permit to fish for these endangered catfish, the village association then sold the fish to the Department of Fisheries, which harvests their eggs and sperm as part of a captive breeding program. After that, the fish are to be returned to the river. But, as usually happens, this fish, a female, did not survive the harvesting procedure, in which its belly is vigorously massaged and manipulated. In the end, the men of the village cut it into giant steaks and sold it. When he tried a bit, Thirayuth said, it tasted soft and sweet and mild. "It's hard to describe," he said. "You have to try it yourself."

Is the Mekong Catfish, the World’s Largest Freshwater Fish?

According to the Guinness Book of Records, the largest specimen freshwater fish ever caught was a pla buk netted in the River Ba Mee Noi, a tributary of the Mekong. The monster was reportedly 9 feet and 10¼ inches long and weighed 242 kilograms (533½ pounds). There have also been reports of fish larger than 295 kilograms (650 pounds).

Seth Mydans wrote in the International Herald Tribune, “In one of the world's more surprising mysteries, nobody really knows which is the biggest species of fish lurking in the waters of the Mekong or the Amazon or the Yangtze or the Congo or the Colorado or Lake Baikal. When the giant catfish was caught in May 2005 [near Hat Khrai, Thailand] ,Zeb Hogan, a biologist, rushed here from an expedition in Mongolia to take a look. It was his first trophy in a project to identify and study the world's largest freshwater fish in the hope of protecting their habitats and slowing their extinction. “[Source: Seth Mydans, International Herald Tribune, August 25, 2005]

Sponsored by the National Geographic Society and the World Wildlife Fund, Hogan has embarked on an 18-month expedition that will take him to five continents and more than a dozen rivers. Some species may already be too rare to study, but he has started with the Mekong, which he said had seven species of huge fish, more than any other river, along with at least 750 other species. The Mekong giant catfish may be the first to disappear from the river, he said. The few that remain can be spotted now only in central Cambodia and here, just below the Golden Triangle, where northern Thailand, Laos and Myanmar meet.

So far, Hogan said, no one has made a credible claim to top this year's trophy. It is five times the size of the biggest catfish recorded in the United States, a 121-pound Mississippi River fish that was also caught in May. "I keep expecting people to send me photos or records of larger fish, but nobody has," he said. The candidate species must grow to at least 200 pounds or longer than 6 feet - fish like sturgeon, lungfish, gars, stingrays, carp, salmon, perch and paddlefish.

Already Hogan has a collection of unconfirmed fish stories - 3-meter catfish in Bulgaria, 500-kilogram stingrays in Southeast Asia and 5-meter arapaima in the Amazon, none of them well documented. "A lot of people say the arapaima is the largest freshwater fish, but when you look at the records, there's no reliable record of any over 200 kilograms, and certainly not over 300 kilograms," he said. Hogan has his own personal candidates, the Chinese paddlefish in the Yangtze and the giant stingray here in the Mekong.

Endangered Mekong Giant Catfish

The Mekong giant catfish is considered among the world's most threatened catfish species due to dam construction and habitat degradation along the Mekong river. The fish has been disappearing fast, from more than 60 a year caught in northern Thailand in the early 1990s to just a few today. According to National Geographic only 11 and eight fish were caught in 2001 and 2002 respectively. In 2003, fishermen captured six giant catfish in Cambodia, all of which were released as part of the Mekong Fish Conservation Project

According to National Geographic: “The world’s largest scaleless freshwater fish lives a tenuous existence in the murky brown waters of Southeast Asia’s Mekong River. Once plentiful throughout the Mekong basin, population numbers have dropped by some 95 percent over the past century, and this critically endangered behemoth now teeters on the brink of extinction. Overfishing is the primary culprit in the giant catfish’s decline, but damming of Mekong tributaries, destruction of spawning and breeding grounds, and siltation have taken a huge toll. Some experts think there may only be a few hundred adults left. [Source: National Geographic website]

International efforts are under way to save the species. Authorities in Laos and Thailand now limit total catches to four a year. In Thailand, a group of fishermen pledged to stop catching giant catfish to honor the king’s 60th year on the throne. However, enforcement of fishing restrictions in many isolated villages along the Mekong is nearly impossible, and illicit and bycatch takings continue.

Seth Mydans wrote in the International Herald Tribune, “Their decline coincides with the completion of the first of a series of dams being built upriver in southern China. Many fish cue their migrations to the rise and fall of the water, Hogan said. The giant catfish are caught in April and May when they swim upriver to spawn just north of here. [Source: Seth Mydans, International Herald Tribune, August 25, 2005]

"The damming and the blasting of rapids have changed the habitat and the river flow," Boonluen Chinarath, the village chief in Hat Khrai, told the New York Times. He had caught as many as 100 giant catfish in nearly a half-century of fishing. "The river rises and falls more quickly than before," he said. "Maybe it's up today and maybe it's down tomorrow."

Mekong Giant Catfish and the People of the Mekong Region

Harmony Patricio told The Mekong giant catfish has a lot of cultural importance for the local people. There is a lot of tradition surrounding how the fish is harvested in the wild. Now the wild population of giant catfish has gotten so low that most countries have made it illegal to catch a giant catfish in the river. I've talked to older fishers in villages that historically harvested the giant catfish, and it's really a sad thing for them that their children aren't going to experience that part of their culture. It was a very communal experience with a lot of ceremony involved. [Source: Jeremy Hance,, April 23, 2013 |~|]

“In some places, the whole community would get together for ceremonies and prayers. You need a lot of people to catch this fish; it's really big and heavy! After a successful harvest of a big fish, people would often share the meat and have a big ceremony and celebration. This really important cultural tradition has disappeared now.” |~|

Image Sources: Wikimedia Commons, archer fish: Warren Photography; giant catfish and stingray; National Geographic and relive earth

Text Sources: National Geographic, Natural History magazine, Smithsonian magazine, Wikipedia, New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, Top Secret Animal Attack Files website, The New Yorker, Time, Newsweek, Reuters, AP, AFP, The Economist, BBC, and various books and other publications.

Last updated November 2012

This site contains copyrighted material the use of which has not always been authorized by the copyright owner. Such material is made available in an effort to advance understanding of country or topic discussed in the article. This constitutes 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner. If you are the copyright owner and would like this content removed from, please contact me.