Mekong giant catfish
A massive freshwater fish native to the Mekong basin, now critically endangered.
The Mekong giant catfish is a huge freshwater species found in Southeast Asia. It holds records for size but faces severe threats from dams and fishing pressure.
- Held the Guinness World Record for largest freshwater fish until 2022.
- Grows extremely fast, reaching 150 kg within six years.
- Adults are completely toothless and graze on river algae.
- Population has dropped by 80% in the last 14 years.
- Illegal to fish in the wild across Thailand, Laos, and Cambodia.
What it is
This enormous catfish belongs to the shark catfish family. Adults display grey or white skin without stripes. They lack teeth and have very few barbels compared to other large river fish. Young individuals possess oral teeth and prominent whiskers, but these disappear as they grow past thirty centimetres. The species reaches immense sizes, with historical catches weighing over two hundred kilograms. One specimen measured nearly three metres long, earning a world record for freshwater size before being surpassed by a stingray.
Where it lives
Historically, this fish inhabited almost the entire four-thousand-eight-hundred-kilometre length of the Mekong River. Its range extended from Vietnam up to Yunnan Province in China. Today, populations are restricted to small, isolated groups in the middle Mekong region. Fishermen occasionally find them in the Tonlé Sap River and Lake in Cambodia. They prefer deep main channels exceeding ten metres in depth. Fragmentation from infrastructure has severely reduced their original habitat.
How it lives
Juveniles feed on zooplankton and exhibit cannibalistic behaviour. After one year, they switch to a herbivorous diet of filamentous algae and periphyton. Their lack of teeth allows them to graze on plants growing on submerged rocks. They migrate hundreds of miles north to spawning grounds during the rainy season. Spawning adults face heavy harvesting pressure. Dams block migration routes and threaten larval survival. Water quality degradation further impacts their daily existence.
Breeding and life cycle
Fish congregate at the start of the rainy season to migrate upstream. They require specific environmental conditions for successful reproduction. Individuals must reach fifty to seventy kilograms before they can breed. Captive breeding programmes exist in Thailand to restock wild populations. However, the fish do not reproduce in lakes. Authorities release thousands of captive-bred specimens into reservoirs annually to support declining numbers.
Fish and people
The species holds cultural significance in Thai folklore, where rituals precede fishing attempts. It appears in ancient art along the river. In Laos, it was historically revered as a noble and mysterious creature. It serves as a popular sport fish in exotic ponds across Southeast Asia due to its size and fighting ability. Fishing is illegal in Thailand, Laos, and Cambodia, though enforcement remains weak. Some Thai fishermen voluntarily stopped catching them to mark a royal anniversary.
Status and threats
The IUCN Red List classifies this catfish as critically endangered. Population data indicates an eighty percent decline over fourteen years. Overfishing and dam construction pose the primary threats. A study suggests dam projects could reduce stocks by forty percent. International trade is banned under CITES Appendix I. Conservation efforts include monitoring and awareness campaigns by organisations like the World Wide Fund for Nature. Breeding programmes aim to mitigate extinction risks.
Questions people ask about Mekong giant catfish
How big does a Mekong giant catfish get?
They can reach lengths of up to three metres and weigh around 350 kg. A female caught in 2005 measured 2.7 metres and weighed 293 kg, setting a record for entirely freshwater fish at that time.
What do adult Mekong giant catfish eat?
Adults are herbivores that feed on filamentous algae and periphyton. They lack teeth and graze on plants growing on submerged rocky surfaces. Juveniles initially eat zooplankton.
Why is the Mekong giant catfish endangered?
Overfishing and habitat loss drive their decline. Dam construction fragments rivers, blocking migration and threatening larvae. Pollution and destruction of spawning grounds also contribute to the population drop.
Is it safe to keep as a pet?
Ownership is restricted in various Australian states due to invasive species fears. While bred for aquariums, they grow too large for typical home tanks and require specialised facilities.
Good reading and sources
- BBC NEWS | Asia-PacificBBC, Article
- Hunt for the big fish becomes a race (Published 2005)The New York Times, Article
- Mekong giant catfish on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Mekong giant catfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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