The invasive suckermouth armoured catfish (Pterygoplichthys spp.), known as Ikan Bandaraya, is colonising Southeast Asian urban freshwater systems, raising ecological and management challenges. In this study, Pterygoplichthys spp. were photographed at Setia Alam Central Park Lake in Selangor, Malaysia. During field inspections on April 10, 2025, many individuals were swiftly apprehended utilizing cast nets. The photographs show high population density, shallow lake margin habitat occupancy, and reproductive-age adult morphology. The species' fast reproduction, benthic dominance, and adaptation to contaminated and hypoxic conditions are supported by earlier investigations. Ecological effects include sediment destabilisation, biodiversity displacement, and trophic perturbations. The species' bioaccumulation of heavy metals and minimal natural predation create public health and sustainability issues. Using photographic evidence and global invasion studies, this study urges legislative intervention, public education, and the use of non-invasive monitoring methods like eDNA. The study sheds light on Pterygoplichthys spp ' spread in Malaysian urban lakes and emphasises the necessity for community-based control.

Keywords: Pterygoplichthys spp, invasive species, Setia Alam, urban lake ecology, photographic documentation.

The introduction of non-native species, particularly invasive ones, into freshwater systems has raised ecological issues on a global scale. The suckermouth armoured catfish Pterygoplichthys spp (Ikan Bandaraya in Malaysia) has spread from South America to tropical and subtropical regions, including Southeast Asia. Pterygoplichthys spp., originally introduced for the ornamental fish trade and aquarium cleaning, have developed self-sustaining and rapidly expanding populations in local waterways.^1,2

Due to their facultative air-breathing and benthic feeding tactics, Pterygoplichthys spp. may survive in deteriorated water conditions with low dissolved oxygen and high sediment loads.^3,4 Their presence in numerous nations has caused the displacement of native species, habitat degradation, and trophic interaction disturbance in local aquatic ecosystems.^5–7 In Thailand and India, these catfish prey on native fish eggs and fry, threatening endemic species' reproduction.^8,9 Similar invasions in Florida and Bangladesh have increased Pterygoplichthys spp biomass without natural predators, causing fish community imbalance and biodiversity loss.^10,2

The species indirectly threatens human health and environmental governance as well as ecology. Research suggests that Pterygoplichthys spp can accumulate heavy metals like cadmium and lead in urban and industrial streams.^11,12 Although not historically eaten in Malaysia, the species has been eaten in Mexico and Bangladesh, prompting worries about its incorporation in subsistence fisheries. Pterygoplichthys spp biomass is increasingly being used for positive purposes, including fish meal production, bone char for pollutant removal, and biomedical research.^12–14 This dual nature—ecological annoyance and potential resource—presents policymakers and local populations with challenges and opportunities.

Pterygoplichthys spp incursions in urban lakes like Setia Alam Central Park (Lake) in Malaysia are poorly documented. This study aims to photographically document the presence, habitat utilisation, and capture density of Pterygoplichthys spp. in the lake. The central research question guiding this investigation is: To what extent does the visual documentation of Pterygoplichthys spp. at Setia Alam Central Park Lake reflect an ecologically established invasive population with implications for native biodiversity and urban freshwater management? By drawing on global case studies and ecological literature, we contextualise local observations within the broader themes of invasion biology, reproductive success, and environmental risk. This article seeks to raise awareness of invasive freshwater species in Malaysia and underscores the urgent need for integrated ecological governance and community engagement to mitigate their long-term impacts.

Photographs were taken at Setia Alam Central Park (Lake) in Selangor, Malaysia, on 10 April 2025. Two sampling locations were selected based on accessibility, visible aquatic activity, and observed sedimentation patterns. Site 1 (3.103150, 101.456885) is located near a drainage outlet surrounded by landscaped areas and nearby construction zones. Site 2 (3.103276, 101.456329) is a narrower water channel bordered by residential dwellings and overhanging vegetation. These contrasting sites were chosen to represent different habitat conditions within the lake ecosystem.

The fieldwork was conducted between 5:15 p.m. and 6:06 p.m., with a total observation time of approximately 50 minutes. Sampling involved five cast net throws per site, using a circular cast net with a radius of approximately 1.8 meters. A team of three individuals conducted the sampling and field observations. Across both sites, 13 individuals of Pterygoplichthys spp. were successfully captured, while an estimated 30 to 40 individuals were visually observed surfacing or disturbed during net deployment—indicating high relative density in the littoral zones.

A Xiaomi 13T Pro smartphone camera was used for all photographic documentation. The device's high-resolution capabilities enabled detailed visual records, which were automatically timestamped and geotagged for data integrity. Photographs included environmental habitat context (Figure 1–4), cast netting procedures (Figure 5–6), and close-up images of the captured catfish specimens for identification purposes (Figure 7–10).

Figure 1 Locations of observational study.

Identification of Pterygoplichthys spp. was performed visually based on standard morphological features commonly described in the literature. These include the presence of armoured bony plates covering the dorsal and lateral surfaces, providing the fish with a rigid exoskeletal structure. A distinctive ventrally located modified sucker-like mouth was observed, characteristic of the genus’ benthic foraging behaviour. The specimens displayed reticulated black and brown patterning along the dorsal region, serving as camouflage against sediment-rich substrates. Additionally, a prominent dorsal fin bearing more than nine soft rays was noted, along with an emarginate caudal fin exhibiting dark pigmentation. The overall body shape was elongated and flattened ventrally, consistent with benthic adaptation and sediment-associated locomotion. These visual features collectively confirmed the identification of the captured individuals as Pterygoplichthys spp.

Although no precise morphometric measurements were taken, a size estimation was conducted using a hand comparison in several images (e.g., Figure 10), indicating individuals ranged between 15 and 20 cm in total length.

Photographs of Site 1 (Figure 1 and 2) revealed a shallow, sediment-laden water body with brownish, turbid water, indicative of high particulate matter. The drainage outlet visible in Figure 2 suggests continuous input from surrounding urban areas, likely contributing to nutrient loading and poor water clarity. Vegetation along the banks was sparse in some areas, but shaded by adjacent tree canopies, creating ideal habitats for bottom-dwelling fish. Overall, Site 1 reflects a moderately disturbed freshwater microhabitat influenced by runoff and nearby construction.

In contrast, Site 2 (Figure 3 and 4) showed a narrower stream-like water body with overhanging vegetation and evidence of bank erosion. The water at Site 2 also appeared turbid, though the presence of more dense plant life may contribute to slightly better shelter conditions for aquatic fauna. The proximity to human settlements and unmanaged bank vegetation may enhance organic detritus input, promoting the survival of hardy invasive species. Both sites share the characteristics of slow-moving, low-oxygen waters, a condition in which Pterygoplichthys spp. can thrive due to their facultative air-breathing ability.

Figure 5 and 6 captured the process of fish collection using a fishing net (cast net) method. Individuals were observed deploying the net along the shallow edges of both sites. The capture of multiple specimens within minutes of casting demonstrates the high local density of the invasive species. The fact that these activities occurred in shallow waters further suggests that Pterygoplichthys spp tends to inhabit zones of minimal depth and low disturbance, where detritus and sediment accumulation offer both cover and feeding grounds.

Close-up photographs of the captured fish (Figure 7–10) confirmed the presence of Pterygoplichthys spp., identified by their armored body plates, distinct sucker mouths, and reticulated black-and-brown patterns across the dorsal surfaces. The specimens were observed to be between 15 to 20 cm in length, with some variability in girth. Figure 10, which includes a hand for scale, shows a full-grown adult of the species. The presence of multiple individuals with similar sizes and healthy appearance reflects a stable and established population within the lake ecosystem.

The photographs document not only the existence but also the visual dominance of Pterygoplichthys spp. in Setia Alam Central Park (Lake). The frequency and ease of their capture further emphasize their ecological proliferation and support concerns regarding their negative impact on native aquatic biodiversity and sediment dynamics.

Ecological dominance and invasion pattern

Images from Setia Alam Central Park Lake show a large population of Pterygoplichthys spp. caught in cast nets in a short time. As in Asia and the Americas, Pterygoplichthys spp. dominates lentic and slow-moving freshwater systems. Due to their adaptability to low-oxygen environments and resilience to pollution, these armoured catfish have high densities in lakes and reservoirs in India,^6,7 Thailand,¹ and Mexico.¹⁵

Burrowing and sediment-disturbing are major ecological consequences. The fish's armoured shape and benthic feeding behaviours destabilise sediments, increasing lakebank erosion and turbidity.^5,6 Setia Alam photos showed similar morphological and behavioural traits, especially on shallow bank margins. These behaviours have been connected to significant aquatic habitat degradation in Sri Lanka¹⁶ and Bangladesh,² where Pterygoplichthys spp. spread and water clarity and vegetation cover decreased.

MaxEnt-based distribution modelling shows that Pterygoplichthys spp. can invade the Indo-Burma hotspot and equatorial freshwater systems.¹⁷ Urban runoff, nutrient-rich inputs, and regulated water bodies make Setia Alam a perfect ecological habitat for this genus. Their facultative air-breathing ability allows them to live in hypoxic conditions, as shown in Florida springs and Mexican reservoirs.^3,4 These physiological and ecological features make Pterygoplichthys spp a better intruder than native fish that need stable oxygen and clear water.

Reproductive strategies and population establishment

This study's subjects—ranging in size and not emaciated—indicate a healthy, reproductively active population. According to reproductive ecology studies in Florida, India, and Sri Lanka, Pterygoplichthys disjunctivus and P. pardalis have continuous or seasonal reproductive cycles depending on water temperature and nutrient availability. The species' high fecundity in anthropogenically changed lakes enables rapid population increase without natural limits, which is problematic.

Eutrophication from urban expansion and reduced predation may help Setia Alam Central Park Lake reproduce. Hussan et al.⁹ noted that habitat nutrient levels, particularly those in urban retention ponds like Setia Alam, affect P. pardalis reproductive output. Warm, nutrient-rich waters have shown gonadal development and spawning readiness in Pterygoplichthys spp populations in Mexico¹⁵ and the Philippines.¹⁸

In Thailand and Colombia, nutritional plasticity and omnivorous feeding promote species fitness.^5,19 The collected individuals' size variation suggests recruitment and population turnover. The ability to use detritus, algae, and manufactured food waste reduces intraspecific competition and stabilises growth, providing a self-sustaining population. Sookying et al.¹³ found that P. pardalis meal supplementation increased Chinese bullfrog growth in aquaculture trials, demonstrating the species' nutritional density and suggesting that similar physiological features allow wild proliferation.

Trophic interactions and disruption of native communities

The Setia Alam cast net samples showed no native fish, supporting the idea that Pterygoplichthys spp may outcompete native species for space and resources. According to Thai trophic disruption reports, Pterygoplichthys spp preys on Clarias macrocephalus eggs and fry, decreasing larval survival.⁸ Indigenous fish stocks are threatened by interspecific conflict and early life stage predation.

Pterygoplichthys spp has few predators in invaded habitats, but rare predator-prey interactions do occur. Centropomus undecimalis in Mexico and Staurotypus triporcatus in Belize have been recorded eating P. pardalis.^20,21 These are opportunistic and insufficient to manage populations. The armoured structure and massive size of adults repel most native piscivores, creating a predator-free ecological niche.

Microplastics have also been eaten by the species in Mexico,²² showing that it changes pollution routes in urban aquatic ecosystems. Pterygoplichthys spp, a bottom-dwelling forager, integrates contaminants into the food web and may aid biomagnification in higher trophic levels, threatening aquatic biodiversity and water quality.

Human health risks and community-based management

Pterygoplichthys spp is rarely eaten in Malaysia, although Mexican riparian populations use it as a protein source.¹¹ Studies indicate that the species can collect heavy metals like cadmium and lead through sediment intake and filter-feeding behaviour,¹² generating concerns about human health hazards if utilised as food. Community outreach and food poverty initiatives should highlight ecological and toxicological impacts of eating this species.

In Bangladesh, surveillance techniques and public education helped discover and remove Pterygoplichthys spp early.¹⁰ Environmental DNA (eDNA) analysis, proven for Pterygoplichthys spp detection in India (Desai et al., 2024), may be cost-effective for non-invasive lake monitoring in Malaysia. Citizen science activities using these technologies could improve early intervention before ecological thresholds are surpassed.

Proactive management is crucial in policy. Potential remedies include restrictions on the illegal fish trade and aquarium trade, biological control experiments, and habitat modification.^1,9 Under stringent regulations, a balance between use and management might be required due to the species' potential as a low-cost protein source or bioresource for water treatment e. g bone char for fluoride removal.¹²

While this study presents useful visual documentation of Pterygoplichthys spp. in Setia Alam Central Park Lake, its findings are observational in nature and limited by the absence of quantitative ecological assessments. Therefore, while concerns about ecological disruption, heavy metal bioaccumulation, and public health risks are supported by prior studies elsewhere, direct impacts in this particular lake remain to be verified through future sampling and analytical work. Nevertheless, the clear presence of the species in large numbers warrants early consideration of public awareness strategies and exploratory monitoring techniques, such as eDNA and citizen science, as potential first steps in assessing and managing this invasion.

This preliminary photographic observation confirms the visual presence and apparent local establishment of Pterygoplichthys spp. in Setia Alam Central Park Lake, Selangor. The number and size of individuals captured within a short period suggest a self-sustaining population adapted to urban freshwater conditions. The species’ observed morphological traits and behavioural tendencies are consistent with those reported in established invasive populations elsewhere. However, inferences about its ecological impact on native biodiversity and sediment dynamics in this particular lake remain tentative due to the limited nature of the dataset.

This study highlights the value of rapid visual surveys in identifying potentially invasive species in Malaysian urban lakes and underscores the importance of early documentation as a basis for future research. While the current data are not sufficient to draw firm ecological conclusions, they provide foundational evidence that can guide more comprehensive ecological assessments and policy attention. Future efforts should include systematic population sampling, water quality testing, and dietary and trophic interaction studies to more accurately assess the species' ecological role and potential risk.

None.

The author declares there is no conflict of interest.

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