Following the recent rains and water movements in the La Boca dam , there has been an increase in reports from residents about the presence of the so-called devil fish , a pleco of South American origin that worries those who use and enjoy these ecosystems.
The species, known in aquariums for its "cleaning" role, has settled in different parts of Nuevo León ; local workers and fishermen maintain that it is not an isolated case and that more specimens are observed each season.
Recent sightings in Nuevo León
On social media, a fishing enthusiast shared images of a specimen caught in the La Boca dam , generating a cascade of comments calling for increased extraction to protect native species.
Local media toured the area and detected at least two fish after the recent drainage; the videos show the bony plates and dark stripes that characterize these loricariids.
Personnel working on recreational boats pointed out that plecos tend to move at greater depths and away from the breakwaters , which explains why they are not always visible to the naked eye.
According to testimonies gathered in the area, their reproduction rate would contribute to more reports appearing each year, something that had already been noted in 2022 and 2023 in the same reservoir.
Affected areas: La Boca, La Silla and Ramos
In addition to the Santiago dam, several specimens were recorded in the La Silla River (Guadalupe) among rocky areas near La Pastora, confirming their presence in urban waterways.
In Montemorelos, residents have reported sightings in the Ramos River , while at the El Cuchillo Dam (China, NL) sporadic captures of this same species have been documented.
The coincidence of records in rivers and reservoirs suggests that, if they are already colonizing urban stretches , the jump to other dams in the state may only be a matter of time.
Effects on the ecosystem and fisheries
The devil fish competes for resources with native fish and can consume eggs and fry of species of ecological and fishing interest, such as bass, tilapia or mojarra.
Their habit of digging galleries for nesting erodes riverbanks and can compromise hydraulic infrastructure; in addition, by removing sediments, they increase the turbidity of the water , affecting species that require clear water.
In systems where the species is expanding, there are reports of decline in catches de peces commercial, adding economic pressure on communities that depend on recreational or livelihood fishing.
Identification, origin and expansion factors
They are plecos of the Loricariidae family , native to the Amazon and Orinoco basins. Over time they can exceed 50–60 cm in length and their skin is covered with spiny plates.
They have brownish coloration with spots or stripes and are usually nocturnal . Although they are not generally aggressive, they defend their territory against other fish.
They withstand adverse conditions: there are records of survival of up to 14 hours out of water thanks to adaptations to obtain oxygen from the air, which favors their persistence.
A common method of introduction is the release of aquarium specimens when they grow too large. Without natural predators and with high reproductive rates, their populations explode rapidly.
The recommendations from specialists and authorities focus on prevention : not releasing exotic fish into rivers or dams, reporting sightings, cleaning and disinfecting equipment before changing bodies of water, and complying with current regulations.
In case of capture during permitted activities, it is advised not to reintroduce the fish and to follow local management guidelines; neighborhood groups promote information actions to reduce further releases.
With sightings in La Boca, La Silla, Ramos and El Cuchillo , the spread of the devil fish in Nuevo León is shaping up to be an environmental challenge that requires monitoring, education and sustained management measures by institutions and citizens.