Ateneo Biologists Confirm Invasive Fish in Laguna de Bay

A striking, silver-colored aquarium fish has been found in the Philippines’ largest freshwater lake, renewing concerns about the unmonitored release of alien species into local ecosystems.

Ateneo de Manila University researchers identified the fish, caught in Laguna de Bay in 2024, as Barbonymus schwanefeldii, also known as tinfoil barb.

Native to Southeast Asia but not the Philippines, the fast-growing omnivore is prized for its metallic appearance in aquariums but poses ecological risks when released into the wild.

Once established, tinfoil barbs can outcompete native fish for food and breeding grounds.

Earlier reports of the species in the Philippines were unverified or anecdotal.

While it is unclear how or when the species entered Laguna de Bay, its confirmed presence underscores a broader trend of invasive freshwater fish establishing themselves in Philippine inland waters.

The long-term ecological impact could be significant.

The research was conducted by Ateneo biologists Kent Elson S. Sorgon, Marjorie Juliana L. Martinez, Andrei Justin F. So, Mariko Franccesca R. Aboganda, Jazreen Nicole G. Parungo, Aeris Johanne G. Poricallan, Keona Tiffany B. Prieto, Mellissa Jewel S. Magday, Alexa Charlize D.C. Geronimo, Ma. Vianca Julia E. Anupol and Derreck O. De Leon.

Their findings were published in the Philippine Journal of Systematic Biology.

“Although ours was the first confirmed sighting of B. schwanefeldii in Laguna de Bay, sightings have also been reported in nearby rivers such as in Pagsanjan, Laguna, and elsewhere,” said lead researcher Sorgon.

He urged local authorities to boost awareness and strengthen monitoring efforts not only for this species but for other invasive aquatic organisms as well.

The researchers warned that the presence of B. schwanefeldii may further strain the already degraded ecosystem of Laguna de Bay, which supports millions of Filipinos through fisheries, water supply and flood control.

If left unchecked, they said, the species could trigger ecological disruptions similar to those caused by invasive fish like tilapia and janitor fish.

These disruptions may lead to biodiversity loss and irreversible changes in aquatic food webs.

The study emphasized the urgent need for biosecurity measures and a national inventory of alien freshwater species to prevent further harmful introductions.

Reference:

Sorgon, J. C., et al. (2025). New records of the tinfoil barb Barbonymus schwanefeldii (Bleeker 1853) in Laguna de Bay, Luzon Island, Philippines. Philippine Journal of Systematic Biology, 18(1). https://archium.ateneo.edu/biology-faculty-pubs/186/

For further inquiries, please contact the paper’s lead researcher, Kent Elson S. Sorgon, at ksorgon@ateneo.edu

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