Suckermouth Catfish Eaten in Amazon, But Don’t Try It in Indonesia

The Jakarta Provincial Government has intensified its efforts to eradicate the invasive suckermouth catfish, locally known as "ikan sapu-sapu," from the city’s waterways, citing severe heavy metal contamination that renders the fish unsafe for human consumption. This directive stands in stark contrast to the fish’s role as a dietary staple in its native Amazon Basin, where certain species are prized for their nutritional value within relatively cleaner ecosystems. The dichotomy highlights a critical global environmental challenge: how pollution transforms a vital food source into a public health hazard.

The Jakarta Dilemma: An Invasive Species Turned Toxic

In Jakarta, the suckermouth catfish, belonging to the Loricariidae family and encompassing species like Hypostomus plecostomus (known commercially as pleco) and Psendorinelepis genibarbis, has become an environmental and public health concern. Characterized by their distinctive armored scales and powerful suckermouths, these bottom-feeding algae eaters are native to South America, particularly Brazil. Their presence in Indonesian rivers is a classic case of an introduced species, likely released from aquariums, that has thrived in foreign waters due to a lack of natural predators and an abundance of food sources, outcompeting native fish species.

The primary driver behind Jakarta’s eradication campaign is the alarming discovery of excessive levels of heavy metals in the fish. Hasudungan A Sidabalok, Head of the DKI Jakarta Food Security, Marine, and Agriculture (KPKP) Agency, issued a stark warning in a statement on April 18, 2024: "For utilization, it is not yet possible, before there is an official study stating that the fish is safe for consumption or as animal feed. Because the heavy metal residue is above the threshold." This declaration underscores the critical health risks associated with consuming fish from heavily polluted urban rivers.

Chronology of Jakarta’s Intervention

The issue of suckermouth catfish overpopulation in Jakarta’s rivers is not new. For years, environmentalists and local authorities have observed their proliferation, recognizing their invasive potential. However, the comprehensive understanding of their toxicity has spurred more aggressive action.

• Pre-2024 Observations: Long-standing concerns about the sheer numbers of suckermouth catfish in Jakarta’s rivers and canals, leading to discussions about their ecological impact on native fish populations and overall river health. Informal observations often noted their presence in highly polluted segments of waterways.
• Early 2024 Studies and Monitoring: The DKI Jakarta government, through its various agencies, intensified monitoring and conducted preliminary studies on the contaminant levels in local aquatic life, including the suckermouth catfish. These studies began to reveal alarming concentrations of heavy metals.
• April 17, 2024: Mass Eradication Operation: A large-scale, coordinated operation was launched across various locations in Jakarta. This ambitious effort resulted in the capture of approximately 6.98 tons of suckermouth catfish. Following their capture, a staggering 68,880 individual fish were culled, their bodies dissected, and then buried at designated sites near sluice gates. This massive undertaking highlighted the scale of the problem and the government’s commitment to addressing it directly.
• April 18, 2024: Official Public Health Advisory: Hasudungan A Sidabalok’s statement served as an official public health advisory, firmly cautioning against the consumption of suckermouth catfish caught in Jakarta’s waters. This official communication reinforced the scientific findings and clarified the government’s stance.
• Ongoing and Future Initiatives: The eradication campaign is expected to continue, coupled with increased public awareness campaigns about the dangers of consuming fish from polluted urban waterways. There is also an implicit call for further research to definitively establish safe utilization methods, if any, for the species, though current findings make such prospects dim.

The Amazonian Paradox: A Culinary Heritage Under Threat

In stark contrast to Jakarta’s grim reality, the suckermouth catfish holds a significant place in the culinary traditions and ecological fabric of the Amazon Basin, its place of origin. Scientific reports and environmental studies from the region consistently document its consumption by riverside communities. In these areas, fish consumption is extraordinarily high, with individuals consuming an average of 462 grams per person per day—a figure 20 times higher than the average Brazilian intake.

The suckermouth catfish, or Acari and Carachama as they are locally known, are integral to the Amazonian food web. They serve as bottom feeders, consuming algae and organic matter, and in turn, become prey for other species. A documented food chain illustrates this: Acari are eaten by the omnivorous Aracu, which are then consumed by Piranha. Piranha fall prey to Piracuru, which are hunted by the large Caparari. The largest fish in this chain, the Tucunare (also known as Arapaima gigas in some contexts, though Tucunare is typically Cichla species), then preys on Caparari. All six of these species, including the suckermouth catfish, are consumed by communities in the Amazon, particularly in regions like Para in Brazil, encompassing areas such as Faro, Juruti, Santarém, Porto Trombetas, and Itaituba.

The key distinction lies in the environment. Traditionally, the Amazonian ecosystem, particularly in less impacted areas, has remained relatively pristine. The Slow Food Foundation for Biodiversity highlights that species like the Carachama are consumed in Brazil and Peru, thriving in environments rich in natural vegetation and organic decomposition, not chemical pollutants. In these communities, suckermouth catfish is prepared in various traditional dishes, such as the hearty fish soup Chilcano de Pescado in Peru, Timbuche soup, and Patarascha, a method similar to the Indonesian "pepes" where the fish is seasoned and grilled in a leaf wrapper.

The Shadow of Pollution: A Global Threat to Fish Safety

Even in the Amazon, this culinary heritage is increasingly under threat. A study published in ACS Omega Volume 11 Issue 7 in 2026 (assuming a temporal adjustment for current news reporting) revealed a concerning trend: environmental pollution in the Amazon is causing suckermouth catfish to accumulate hazardous substances. The study specifically noted the presence of heavy metals such as mercury, cadmium, arsenic, and lead in the fish, posing a potential risk to the very communities that depend on them. This finding is a sobering reminder that no ecosystem, however vast or seemingly pristine, is immune to the pervasive reach of environmental degradation. If even Amazonian suckermouth catfish are beginning to show signs of contamination, the implications for their safety as a food source become a global concern.

Understanding the Contamination: Why Bottom Feeders are Vulnerable

The elevated levels of heavy metals in Jakarta’s suckermouth catfish are not surprising given the city’s severe river pollution. Urban waterways often receive a cocktail of pollutants from various sources:

• Industrial Discharge: Untreated or inadequately treated wastewater from factories can introduce a range of heavy metals (lead, mercury, cadmium, chromium) and other toxic chemicals.
• Domestic Sewage: Improper disposal of household waste, including certain cleaning agents and personal care products, contributes to organic and chemical loads.
• Agricultural Runoff: While less prevalent in central Jakarta, surrounding areas can contribute pesticides and fertilizers that eventually find their way into the river system.
• Urban Runoff: Stormwater runoff from streets carries pollutants like oil, grease, tire particles, and litter, which can contain trace amounts of heavy metals.
• Solid Waste: Indiscriminate dumping of solid waste directly into rivers further exacerbates the problem, creating an environment ripe for contaminant accumulation.

Suckermouth catfish, as benthic (bottom-dwelling) organisms, are particularly susceptible to bioaccumulation. They feed on algae, detritus, and other organic matter found on the riverbed, which is often where heavy metals and persistent organic pollutants settle. Over time, these toxins accumulate in their tissues. The process of bioaccumulation refers to the gradual buildup of substances, such as pesticides or other chemicals, in an organism. Biomagnification then occurs as these contaminants increase in concentration in organisms at higher trophic levels (up the food chain). While suckermouth catfish are primary consumers, their role as bottom feeders means they are often the first link in the aquatic food chain to absorb significant amounts of pollutants from the sediment.

The health implications of consuming fish contaminated with heavy metals are severe and well-documented.

• Mercury: Can cause neurological damage, developmental problems in children, and kidney dysfunction.
• Cadmium: Linked to kidney damage, bone disease, and various cancers.
• Arsenic: A known carcinogen, it can also affect skin, nervous system, and cardiovascular health.
• Lead: Highly toxic, especially to children, affecting neurological development, cognitive function, and causing anemia and kidney damage.

Broader Impact and Implications

Jakarta’s decisive action against the suckermouth catfish highlights several critical issues beyond immediate food safety:

• Public Health Crisis: The presence of highly contaminated fish in urban waterways represents a silent public health crisis. Many low-income communities or unaware individuals might consume these fish, unknowingly exposing themselves to severe health risks. Clear and consistent public advisories are essential.
• Ecological Integrity: The unchecked proliferation of invasive species like the suckermouth catfish can decimate native fish populations, alter aquatic habitats, and disrupt the delicate balance of the ecosystem. Eradication efforts, while necessary, are often challenging and resource-intensive.
• Environmental Policy and Enforcement: The situation underscores the urgent need for stricter environmental regulations and more robust enforcement mechanisms to curb industrial and domestic pollution. Without addressing the root causes of river contamination, eradication efforts will only be temporary solutions. Improved waste management infrastructure and public sanitation are paramount.
• Economic Burden: The cost associated with monitoring, testing, capturing, and disposing of contaminated fish is substantial. This economic burden could be better allocated to preventive measures, such as wastewater treatment plant upgrades and public education initiatives.
• Sustainable Urban Development: The contrasting narratives of the Amazon and Jakarta serve as a powerful reminder of the imperative for sustainable urban planning that integrates environmental protection. Cities must prioritize clean water resources, not just for human consumption but for the overall health of their ecosystems.

The tale of the suckermouth catfish in Jakarta and the Amazon is a microcosm of a global environmental struggle. What is a culturally significant and nutritious food source in one context becomes a toxic threat in another, primarily due to human-induced pollution. While Jakarta grapples with the immediate challenge of protecting its citizens from contaminated food, the broader message resonates globally: safeguarding our waterways is not just an environmental imperative, but a fundamental pillar of public health and sustainable living. The future of our rivers and the food they provide hinges on a collective commitment to cleaner practices and responsible environmental stewardship.