Over 7 Tons of Invasive ‘Janitor Fish’ Extracted From Indonesian Waterways, and It’s Just the Beginning

**Jakarta Mobilises Efforts to Eradicate Invasive Suckermouth Catfish Threatening Local Ecosystems**

Jakarta has embarked on an urgent campaign to remove an estimated 10 tons of invasive suckermouth catfish, known locally as “sapu-sapu” or “janitor fish.” This initiative is motivated by growing concerns about the impact these fish have on local biodiversity and the overall health of the city’s waterways. The species, which originated from South America, has been proliferating in Indonesia’s rivers and canals, exacerbating existing environmental issues.

The invasive fish species, formally known as Pterygoplichthys gibbiceps, can grow up to 20 inches long and live for as long as 15 years. Initially introduced decades ago as a means to control algae in aquarium tanks, they were eventually released into natural water bodies. Since then, they have demonstrated a remarkable ability to thrive in polluted environments—a factor that has alarmed environmental specialists.

The Ciliwung River, an essential waterway that once boasted clear mountain waters, has suffered significantly due to urban pollution. Currently, it carries untreated waste and industrial runoff through dense residential areas, creating conditions that favour the invasive fish over native species. Dian Rosleine, an ecologist at the Bandung Institute of Technology, highlighted the menace posed by suckermouth catfish, which survive and reproduce in conditions that other species cannot tolerate. “These fish are biological indicators that the water is in poor condition,” Rosleine explained.

In mid-April, crowds gathered in East Jakarta’s Ciracas neighbourhood to witness local authorities, firefighters, and volunteers collectively extract large quantities of these invasive fish from a reservoir. In just one day, approximately 705 pounds of fish were removed from the 19-foot-deep reservoir, a testament to the urgency of the campaign. East Jakarta Mayor Munjirin commented on the alarming reproduction rates of the janitor fish and their subsequent predation on local species, alongside structural damage to riverbanks.

While the removal efforts have garnered community support, the campaign has not been without its controversies. The Indonesian Ulema Council, the country’s highest Islamic clerical authority, expressed concern that burying the fish alive contravenes Islamic principles regarding animal welfare. In light of these concerns, Jakarta Governor Pramono Anung announced that measures would be taken to ensure all fish would be confirmed dead before disposal.

Additionally, issues surrounding the potential contamination of the fish with heavy metals have led officials to reconsider direct consumption. As a result, there is a focus on processing the invasive species into animal feed or fertiliser, thereby utilising them in a more sustainable manner.

Although the current initiative aims to reduce the population of suckermouth catfish, experts caution that removal alone will not solve the underlying problems faced by the Ciliwung River. Rosleine noted that without rehabilitative measures focusing on pollution control and restoration of the freshwater ecosystem, the efforts may yield only temporary results. “Addressing the symptoms without tackling the root causes will not provide a lasting solution,” she stated.

The ongoing presence of the suckermouth catfish underscores broader environmental challenges in Indonesia’s urban waterways. As the city strives for ecological restoration and improved water quality, it is essential that future strategies address both the invasive species and the pollution plaguing Jakarta’s rivers. The city’s residents, alongside officials and environmentalists, will need to advocate for sustainable practices and long-term solutions to ensure a healthier ecosystem.

As Jakarta continues its round-the-clock efforts to reclaim its waterways, the impact of these actions remains to be seen. The community’s response highlights a collective desire to preserve their natural environment, while officials are reminded of the complexity involved in addressing ecological imbalances. The campaign may be just the beginning of Jakarta’s road to environmental recovery.