Researchers flag threatening fish species in Laguna de Bay

Metro Manila, Philippines - Biologists from a university flagged a fish species in the country’s largest freshwater lake that could potentially threaten breeding ground and food for native fish.

The scientists from Ateneo de Manila University said the presence of tinfoil barb in Laguna de Bay, which they said was “alien fish” normally bred in aquariums, “can rapidly outcompete native fish for food and breeding grounds” once released into the wild.

They said the tinfoil barb “could further stress the already degraded ecosystem” of the lake, which is a multi-use water resource for fish supply and domestic water supply.

“Their study underscores the urgent need for comprehensive biosecurity policies and a national inventory of freshwater alien species before more irreversible introductions occur,” the Ateneo said in a news release on Tuesday, July 1.

Barbonymus schwanenfeldii, or tinfoil barb, is a native species to many parts of Southeast Asia. The fast-growing omnivorous species is commonly kept as an aquarium pet for its eye-catching metallic appearance.

“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,” lead researcher Kent Sorgon was quoted as saying in the news release.

“We hope that local authorities can help raise awareness and put in further monitoring efforts, not just for this but for other invasive species as well,” he said.

Researchers examined a specimen collected from a catch of fisherfolk in a fishery landing site in Cardona, Rizal in September 2024.

In July last year, the biologists noted anecdotal reports of the species caught in Talim Island, almost in the center of Laguna de Bay, which was four to five kilometers away from the source of the collected specimen.

The researchers noted in their study that the species “has not been recorded in Laguna de Bay until now despite more than 70 years of observations by different authors.” They added the mode of introduction is unknown.

“The large area of Laguna de Bay and the migratory behavior of this species, coupled with a generalist feeding habit suggest that it may be more widespread and may have moved into rivers that feed into the lake, in turn exacerbating its spread,” they said.

The Bureau of Fisheries and Aquatic Resources (BFAR) said in a statement Wednesday that it is “actively responding” to the reported presence of tinfoil barb in Laguna de Bay.

The agency said it has been monitoring the presence of the species and evaluating its potential ecological and socio-economic impacts since the initial documentation in 2021.

“With recent reports indicating an increase in the presence of tinfoil barb, DA-BFAR has intensified its efforts and is closely coordinating with concerned local government units and the Laguna Lake Development Authority, the primary agency mandated to oversee the lake’s management and water resources,” the BFAR said.