Jakarta Orders Mass Removal of Invasive Janitor Fish From Ciliwung River Reservoirs

Indonesia’s capital, Jakarta, launched a mass removal operation targeting invasive “janitor fish,” locally known as “sapu-sapu,” after residents, city workers and environmental volunteers hauled bulging nets of the fish to the surface of a reservoir.

“Please enable cookies”

AccessWDUN

Authorities are seeking to remove at least 10 tons (9 metric tons) of the fish from Jakarta’s waterways, aiming to restore balance to the Ciliwung River and renew public attention on water quality.

Associated Press

The fish are not native to Indonesia, and the AP report says they were “Imported decades ago for aquariums because of their ability to consume algae,” before being released and finding a home in Jakarta’s heavily polluted rivers.

The AP describes the fish as having armored bodies “gleaming a dull brown beneath the murky surface,” and says they can grow up to 50 centimeters (nearly 20 inches) and live for 10-15 years.

The Herts Advertiser likewise frames the operation as a crackdown, saying “Authorities are seeking to remove at least 10 tonnes (nine metric tonnes) of the fish from Jakarta’s waterways,” and adds that the fish are “known scientifically as Pterygoplichthys and locally as ‘sapu-sapu’.”

In the same AP account, the campaign began last week and was ordered by Jakarta Gov. Pramono Anung, with the cleanup carried out simultaneously in all five administrative cities of the capital.

Within a week, AP says teams “have netted and buried more than seven tons of janitor fish across the city,” while the Herts Advertiser reports “more than seven tonnes of janitor fish across the city within a week.”

Both reports connect the janitor fish surge to Jakarta’s water conditions and to the species’ ability to survive in polluted environments.

The AP says the Ciliwung River “once carried clear water from the mountains of West Java into Jakarta,” but now “flows through dense neighborhoods, carrying untreated household waste and industrial runoff,” with “Concrete walls replaced riverbanks.”

Herts Advertiser

It adds that during dry months, the water “warms and slows — conditions that favor janitor fish over native species,” according to ecologist Dian Rosleine.

Rosleine, described by AP as “an ecologist from the Bandung Institute of Technology,” says “the adaptability of janitor fish is very high, so that even in polluted conditions, it can survive when other species can’t.”

The Herts Advertiser repeats the same ecological framing, stating that “The Ciliwung once carried clear water from the mountains of West Java into Jakarta” and that today it carries “untreated household waste and industrial run-off.”

It also quotes Rosleine’s assessment that “So, these fish are biological indicators that the water is in poor condition,” and it similarly attributes the advantage to dry-season conditions that “favour janitor fish over native species.”

The AP further situates the problem within broader warnings about invasive species, saying “Experts have long warned that unchecked populations of invasive species can destabilize freshwater ecosystems.”

The cleanup operation drew public attention as workers hauled fish from a reservoir in East Jakarta’s Ciracas neighborhood.

“Cheers broke out in Indonesia’s capital as residents, city workers and environmental volunteers hauled bulging nets of invasive fish to the surface of a reservoir in an operation to crack down on “janitor fish””

Herts Advertiser

The AP says the cleanup on Friday took place at a “6-meter-deep (19-foot-deep) reservoir in East Jakarta’s Ciracas neighborhood,” and it reports that the event “drew curious crowds as city workers collected about 320 kilograms (705 pounds) of the fish.”

It describes the fish being stored in visible containers, saying “Piles of wriggling janitor fish filled red barrels along the reservoir — tangible proof that something, at last, was being done.”

The Herts Advertiser similarly reports that the cleanup on Friday at a reservoir in East Jakarta’s Ciracas area drew crowds, and it gives a slightly different measurement for the reservoir depth, saying “a 20ft deep reservoir.”

In that same Herts Advertiser account, city workers collected “about 320 kilograms (705lbs) of the fish,” and it likewise describes “Piles of wriggling janitor fish filled red barrels along the reservoir.”

Both reports attribute statements about the fish’s impact to East Jakarta’s mayor, Munjirin, who uses a single name.

The AP quotes Munjirin saying, “The janitor fish populations have reproduced at a notable level while also feeding on native species,” and it adds that “The impact extends beyond ecosystem destruction, contributing to structural damage to riverbank and embankment walls.”

While Jakarta authorities pursued mass removal and burial, the AP reports that the Indonesian Ulema Council, or MUI, raised concerns over perceived cruelty and issued a fatwa commission warning about animal rights.

The AP says Munjirin “vowed a review of the program’s method after the Indonesian Ulema Council, or MUI, raised concerns over perceived cruelty, pledging that all fish will be dead before burial.”

Associated Press

It adds that “While endorsing the cleanup, MUI’s fatwa commission warned that burying the janitor fish alive amounts to a violation of animal rights enshrined in Islamic teaching.”

The Herts Advertiser repeats the same sequence, stating that Munjirin “vowed a review of the program’s method after the Indonesian Ulema Council, or MUI, raised concerns over perceived cruelty, pledging that all fish will be dead before burial.”

It likewise says “MUI’s fatwa commission warned that burying the janitor fish alive amounts to a violation of animal rights enshrined in Islamic teaching.”

The AP also quotes Jakarta Gov. Pramono Anung describing the planned method, saying “Anung said that the cleanup method will require the fish to be dead before burial at designated sites, with hygiene standards applied to block their return to rivers or trade.”

Both reports also describe how authorities are cautious about what happens next because janitor fish are edible in some countries but heavy metal contamination concerns mean they “won’t be immediately approved for consumption in Jakarta.”

Even as the operation proceeds, both reports emphasize that removal alone will not fix the underlying water problems in Jakarta’s river system.

“Please enable cookies”

AccessWDUN

The AP says authorities are still cautious about what happens next because “As janitor fish are edible in some countries, concerns over heavy metal contamination mean they won’t be immediately approved for consumption in Jakarta,” and it describes officials exploring alternatives such as processing the fish into “animal feed or fertilizer.”

Herts Advertiser

It also reports that Anung suggested buried fish could serve as “natural compost” and that he suggested adopting “Brazil’s model, where the fish are turned into charcoal to generate greater economic benefits.”

The AP then turns to the limits of the cleanup, stating that “Yet experts caution that removal is only a beginning,” and it warns that “Without improving wastewater management and reducing pollution, the river could quickly return to the same condition.”

Rosleine delivers the clearest warning in the AP, saying, “The Ciliwung River requires rehabilitation, our major challenge that must be addressed,” and adding, “Addressing the symptoms without tackling the root causes will not provide a lasting solution.”

The Herts Advertiser includes the same expert caution and the same Rosleine quotes, including “The Ciliwung River requires rehabilitation, our major challenge that must be addressed,” and “Addressing the symptoms without tackling the root causes will not provide a lasting solution.”

In both accounts, the operation is framed as a coordinated effort that began last week and involved hundreds of personnel, including firefighters, disaster officers and local residents, but the longer-term outcome depends on broader changes to wastewater and pollution.