Not Just Plecos: Alien Red Devil Fish Damage Lake Toba and Jatiluhur Reservoir
Jakarta, CNBC Indonesia - The pleco fish is currently a hot topic due to its growing population in waterways and its perceived disruption to ecosystem balance. However, according to the National Research and Innovation Agency (BRIN), the government’s attention must not stop at merely cleaning the capital’s canals.
PRLSDA BRIN researcher Triyanto revealed that the pleco is just one of many “coloniser” fish in our inland water ecosystems.
“So that society, the government, and environmental observers do not focus solely on the pleco. Because the pleco is just one example among several invasive fish that have actually been present in Indonesia,” Triyanto stated in a comment, quoted on Saturday (25/4/2026).
Based on a scientific publication compiled by the BRIN research team, there are at least 50 types of alien species that have entered Indonesia’s waters. Of that number, 18 types have been identified as having invasive characteristics.
The scientific study emphasises that once invasive populations dominate an ecosystem, control becomes extremely difficult. This is because efforts must be made holistically from the root causes.
One of the serious threats besides the pleco is the Red Devil fish. This species has been reported to damage local fish populations in strategic locations.
“You may have heard of the Red Devil fish that is rampant in Lake Toba, Jatiluhur Reservoir, and Cirata Reservoir. Or perhaps in other Indonesian waters like Lake Batur. Its population has also increased in those locations,” Triyanto explained.
He stated that the presence of these invasive alien species (IAS) is a case that has spread widely and requires integrated control policies, not just ceremonial actions in one region.
“The presence of these invasive alien fish, in our view, must be anticipated or their populations controlled immediately. So the pleco that is rampant in Jakarta is just one part of the existing cases of invasive fish spread,” he concluded.