Malaysia’s ‘fish hunters’ battle with invasive species

In Malaysia, rivers are under threat from invasive fish species that have spread widely, harming native wildlife and local ecosystems.

Just outside Kuala Lumpur, a dedicated group of volunteers, known as the “foreign fish hunter squad,” gathers regularly to catch these invasive fish — mainly the suckermouth catfish. This species, originally from South America, has become a serious problem because it multiplies quickly, survives well in polluted waters, and damages riverbanks by burrowing.

Leader Mohamad Haziq A Rahman started the group during the COVID-19 lockdown when he noticed almost every fish he caught was this invasive catfish. What began as a personal hobby grew into a movement with over 1,000 members actively working to reduce the population of these unwelcome fish.

Experts warn that invasive species now occupy more than 80% of rivers in the Klang Valley, with other Malaysian waterways facing similar threats. These fish not only compete with native species for food but also contribute to environmental damage, including erosion that worsens flooding risks.

The fish hunters catch tons of suckermouth catfish regularly. Instead of simply discarding them, they are exploring creative uses—such as turning the fish into charcoal, fertiliser, or even leather. In some cases, they prepare and eat the fish, but only if it’s caught from less polluted rivers.

Malaysia’s fisheries department supports these efforts by releasing millions of native fish to help restore balance and offering incentives to anglers who remove invasive species. Despite these measures, experts say completely eradicating invasive fish is nearly impossible, especially as climate change may allow some species to spread further.

Still, Haziq and his team remain committed. “We may not get rid of them all,” he says, “but acting now to reduce their numbers is better than doing nothing. Otherwise, the problem will only get worse.”

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