IUCN · Critically Endangered · declining

Mekong giant catfish

Pangasianodon gigas · Mekong River basin, Southeast Asia

?left in the wild — unknown
but decreasing (IUCN, 2011)

One of the largest freshwater fish on Earth, now surviving in small, scattered groups in the middle and lower Mekong.

Source: IUCN Red List (April 2011)

Mekong giant catfish swimming in a murky river

Illustrative depiction

Overview

The giant of the Mekong

The Mekong giant catfish is one of the "shark catfishes", named for the way they swim, and one of the largest freshwater fish in the world. It grows astonishingly fast, reaching 150–200 kg in six years, and is reported to weigh up to 350 kg. It can live for about 60 years.

Found only in the Mekong basin of Cambodia, Laos, Thailand and Viet Nam, it needs deep water and migrates across borders, though its routes are still poorly understood. Young fish eat zooplankton and switch to plants after about a year; their whiskers and teeth disappear by the time they reach 50 cm. It is a flagship species for the lower Mekong, revered in Thai folklore and shown in ancient art along the river.

Nobody knows exactly how many are left. The IUCN listed it as Critically Endangered and decreasing in April 2011. Between 1999 and January 2025, 132 wild fish were recorded as bycatch in Cambodia, and more than 83% survived release (Chan et al., 2026). Catches have risen since 2021, but it is not clear whether that means more fish.

Why it is critically endangered

Cut off by dams and nets

Its numbers are thought to have fallen by about 80% in 15 years.

Dams

Dams block its migrations across borders, so its range has collapsed and the population is broken into small scattered groups.

Overfishing

Heavy fishing in the Mekong has helped drive an estimated 80% fall in numbers.

Accidental capture

Stationary bagnets and seine nets cause 91% of bycatch, mostly from October to January when the fish migrate (Chan et al., 2026).

Pollution

Run-off from farming and forestry lowers the water quality of the river.

Conservation history

Caught, counted and released

Year	Event
1999	Monitoring of incidental catches in Cambodia begins; 132 wild fish are recorded as bycatch up to January 2025 (Chan et al., 2026).
2011	IUCN assesses the species as Critically Endangered and decreasing, after an estimated 80% decline.
2022–2024	Incidental captures rise: 9 in 2022, 11 in 2023 and 14 in 2024.
Dec 2024	Six giant catfish are caught and released in Cambodia, a sign of hope for the species.
Dec 2025	Mohamed bin Zayed Species Conservation Fund awards a grant to sustain the last wild population in Cambodia.
2026	Chan et al. report that over 83% of bycaught fish survive release.
Sep 2026	A 136 kg giant catfish is released in Pursat, Cambodia.
Oct 2026	Several endangered giant fish, including a Mekong giant catfish, are caught by accident and released in Krakor district, Cambodia.

Take action

Who's fighting for the Mekong giant catfish

Fisheries scientists, funders and fishing communities working to free bycaught fish and keep the river open.

Critical Ecosystem Partnership Fund

Funds community projects: local law education, capacity building and catch-and-release support in migratory corridors such as Kampong Cham.

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WWF Laos

Works to protect the Mekong and the livelihoods and wildlife that depend on it.

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Mohamed bin Zayed Species Conservation Fund

Grant (Dec 2025) for local education, incident reporting and rapid-response teams to reduce capture deaths in Cambodia.

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Wonders of the Mekong & Cambodian Fisheries Administration

Joint programme with the Inland Fisheries Research & Development Institute; has caught, tagged and released about 100 giant catfish.

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