Residents, city workers, and environmental volunteers recently gathered in Jakarta to remove massive quantities of invasive “janitor fish” from the city’s waterways. The operation, which saw cheers break out on Friday as nets were hauled from a reservoir, is part of a broader crackdown to restore ecological balance to the Ciliwung River.
A City-Wide Cleanup Operation
Ordered by Jakarta Governor Pramono Anung, the cleanup drive has been carried out simultaneously across all five administrative cities of the capital. The effort involves hundreds of personnel, including disaster officers, firefighters, and local residents.
Within a single week, authorities have already netted and buried more than seven tons of the fish. The overall goal is to remove at least 10 tons (9 metric tons) from the city’s waterways to renew public focus on water quality.
On Friday, workers focused on a 6-meter-deep (19-foot-deep) reservoir in East Jakarta’s Ciracas neighborhood. During this specific effort, approximately 320 kilograms (705 pounds) of the fish were collected and placed into red barrels.
Ecological and Structural Impact
These armored, dull-brown fish are not native to Indonesia and can grow up to 50 centimeters (nearly 20 inches) with a lifespan of 10 to 15 years. They have found a haven in Jakarta’s polluted rivers, where they cling to concrete embankments and skyscraper-lined canals.
East Jakarta’s mayor, Munjirin, warned that the population has grown significantly, leading to the consumption of native species. Beyond the ecological destruction, Munjirin noted that the fish contribute to structural damage of embankment and riverbank walls.
Ecologist Dian Rosleine from the Bandung Institute of Technology explained that the fish’s high adaptability allows them to survive in polluted conditions that kill other species. As of this, she describes the fish as biological indicators of poor water quality.
Ethics and Disposal Challenges
The method of disposal has sparked a review after the Indonesian Ulema Council (MUI) raised concerns. The MUI’s fatwa commission warned that burying the fish alive violates animal rights enshrined in Islamic teaching.
In response, Mayor Munjirin and Governor Anung pledged that all fish will be dead before burial at designated sites. Hygiene standards will be applied to ensure the fish do not return to the rivers or enter trade.
While edible in some countries, these fish will not be approved for human consumption in Jakarta due to concerns over heavy metal contamination. Instead, officials are exploring alternatives such as fertilizer, animal feed, or natural compost.
The Path Forward
Governor Anung suggested that Jakarta could adopt a model used in Brazil, where these fish are turned into charcoal to generate economic benefits.
However, experts warn that mass removal may only be a temporary fix. Without significant improvements to wastewater management and a reduction in industrial runoff and household waste, the rivers could quickly return to their current state.
Dian Rosleine emphasized that the major challenge remains the full rehabilitation of the Ciliwung River, stating that addressing symptoms without tackling root causes will not provide a lasting solution.
Frequently Asked Questions
What is a “janitor fish”?
Also known as the suckermouth catfish or Pterygoplichthys, these are non-native fish imported for aquariums that can grow up to 50 centimeters long and live for 10-15 years.
Why are these fish harmful to Jakarta?
They destabilize freshwater ecosystems by feeding on native species and can cause structural damage to the walls of riverbanks and embankments.
Why can’t the fish be used for food?
Authorities are cautious about human consumption because of the risk of heavy metal contamination in Jakarta’s polluted waterways.
Do you believe urban cleanup drives are effective if the underlying pollution isn’t addressed first?
