<p>Photo: Two boys carrying river catfish</p>

Two boys lug weighty river catfish in Cambodia. Once a staple food in Cambodia, catches of these large, slow-maturing fish have dropped 90 percent in the past 20 years.

Photograph courtesy Zeb Hogan


Map: Giant catfish range

Fast Facts

Average life span in the wild:
5 ft (1.5 m)
Up to 99 lbs (45 kg)
Did you know?
One in every four freshwater fish, and one in every ten of the world's fish, is a catfish.
Size relative to a 6-ft (2-m) man

Please add a "relative" entry to your dictionary.

The river catfish may be overshadowed by its famed cousin, the Mekong giant catfish, which shares the same river system in Southeast Asia. But this less celebrated species is a remarkable fish in its own right and, at 5 feet (1.5 meters) and 99 pounds (45 kilograms), it has no apologies to make in the size department.

River catfish are known to inhabit Tonle Sap Lake in Cambodia. Every year they leave the lake and enter the Mekong River as part of their annual spawning cycle. Breeding begins at the onset of the region's rainy season (May-July).

These unique fish have the nickname "iridescent shark catfish," a seemingly ill-suited comparison for a toothless, freshwater fish. The nickname arises from its tendency to swim close to the surface, raising its dorsal fin above the water. As for iridescence, river catfish have no scales, but their delicate skin is covered with a protective layer of slime that gives them a shiny glow.

These fish are threatened with habitat fragmentation, industrial pollution, and overfishing. Many millions of people depend on the Mekong River for sustenance, and river catfish have long been targeted for their succulent meat.

They are extensively farmed along some sections of the river, such as in Thailand, where wild specimens have become quite rare.

National Geographic Emerging Explorer Zeb Hogan is attempting to learn more about these catfish by conducting a large-scale tagging and monitoring study. Since 2004, his team has tagged more than 3,000 river catfish in hopes of documenting their behavior and helping authorities to provide better protections.

Help Save the Colorado River

You can help restore freshwater ecosystems by pledging to cut your water footprint. For every pledge, Change the Course will restore 1,000 gallons back to the Colorado River.

Freshwater Advocates

  • Picture of Peter McBride in Kenya

    Freshwater Hero: Pete McBride

    Pete is a photographer and visual storyteller with an emphasis on freshwater conservation.

  • sandra new headshot.jpg

    Sandra Postel

    Sandra is a leading authority on international freshwater issues and is spearheading our global freshwater efforts.

  • Photo: Osvel Hinojosa Huerta

    Osvel Hinojosa Huerta

    For more than 15 years, Osvel Hinojosa Huerta has been resurrecting Mexico's Colorado River Delta wetlands.

For More Inspiration »

Change the Course Infographic


Check out this infographic and learn how you can conserve water and save the Colorado River, as well as other freshwater ecosystems.

Share it with your friends!

Explore Freshwater

More Posts »

Test Your Water IQ

  • Photo: Aerial view of canyon

    Freshwater 101 Quiz

    Where does water sit around the globe? How is it used to produce everyday goods? Test your knowledge about freshwater.

  • Photo: People waiting for water truck

    Drinking Water and Sanitation Quiz

    For much of the world, drinking a glass of water is not as easy as filling up at a water cooler or even the kitchen sink.

Change the Course logoChange the Course: Help Save the Colorado River