Taxonomy & naming
Chaetostoma stroumpoulos was formally described by Norma J. Salcedo in 2006 in Ichthyological Exploration of Freshwaters (volume 17, number 3, pages 207–220). It was described alongside Chaetostoma daidalmatos, both new species from the Huallaga River drainage of central Peru. The Catalog of Fishes (Eschmeyer, CAS) recognises the valid combination Chaetostoma stroumpoulos Salcedo, 2006.
The genus Chaetostoma is large and taxonomically complex, comprising around 51 valid species distributed across Andean and sub-Andean river systems of South America. The generic name is derived from the Greek chaite (hair or bristle) and stoma (mouth), an allusion to the bristle-like interopercular odontodes prominent in males. The species epithet honours a personal name, as is common in ichthyological nomenclature, though no public etymology statement has been identified in accessible sources.
The species was noted again by Ortega et al. (2012) in a survey of Peruvian fish fauna, confirming it only from its type locality. No further specimens or populations have been recorded beyond the Huallaga River near Tingo María, Huánuco Region.
Morphology
No maximum size has been recorded for Chaetostoma stroumpoulos in FishBase or in the available IUCN assessment materials. The species belongs to the rubbernose or bulldog pleco group (Chaetostoma), a genus of compact, depressed-bodied loricariids adapted to fast-flowing Andean and piedmont rivers. The genus characteristically has a broad, rounded rostrum, a ventrally positioned suctorial mouth with numerous small teeth, and the sturdy flattened body profile common to rheophilic loricariids that cling to rocks in strong current.
Interopercular odontodes — the stiff, hair-like spines projecting from the cheek region — are a diagnostic generic feature and are typically more developed in males. The body surface is covered in bony scutes. Colour pattern details that distinguish C. stroumpoulos from congeners were documented in the original description by Salcedo (2006) alongside C. daidalmatos; the two are said to differ in distinctive morphology and coloration, though specific diagnostic detail is not available from secondary sources examined here.
Given that no FishBase size record exists for this species, any size estimate would be speculative. Congeners in comparable sub-Andean systems typically fall in the range of 3–6 in TL, but this figure cannot be applied to C. stroumpoulos without verification.
Habitat
Chaetostoma stroumpoulos is known from the Huallaga River near Tingo María, in the Huánuco Region of central Peru. The Huallaga is a major sub-Andean tributary of the Marañón, itself a headwater of the Amazon. At Tingo María, the river flows through a narrow canyon zone where the Andes descend steeply into the humid montane forest — a transitional zone between highland river and Amazonian lowland, characterised by clean, turbulent, well-oxygenated water over cobble and bedrock substrates.
This is quintessential Chaetostoma habitat: a fast-flowing, clear-to-moderately-turbid piedmont river with high dissolved oxygen, rocky substrate offering attachment surfaces, and abundant algae growth on sun-lit boulders. The sub-Andean elevation at Tingo María (approximately 2198 ft above sea level) means water temperatures are cooler than lowland Amazonian rivers, likely in the range of approximately 68–79 °F, though specific measurements for this reach are not available in published sources for this species.
The IUCN assessment estimates the extent of occurrence at approximately 211 mi², encompassing the main channel and an assumed three tributary locations around the type locality — an extremely restricted range that makes the species inherently vulnerable to any localised disturbance.
Feeding
Chaetostoma species are algae-grazing rheophiles. The ventral suctorial mouth, armed with numerous fine teeth and a muscular buccal disc, is adapted for rasping periphyton — the dense communities of diatoms, green algae, cyanobacteria, and associated organic material that coat rocks and boulders in fast-flowing Andean rivers. This biofilm and epilithic algae layer can be highly productive in clear, sunlit sub-Andean streams despite the relatively high elevation.
In addition to algae, Chaetostoma consume fine detritus, fungal hyphae, and microinvertebrates incidentally ingested while scraping substrate surfaces. The strong attachment ability provided by the suctorial mouth and depressed body allows these fish to maintain position on exposed boulders in currents that would dislodge most other fish, giving them access to algae in microhabitats unavailable to less specialised competitors.
No feeding studies specific to C. stroumpoulos have been published, but this trophic profile is consistent across the genus and is well supported by gut content analyses of congeners.
Mating
Specific mating observations for Chaetostoma stroumpoulos are not available in the published literature, and the species is essentially unknown in the aquarium hobby. No iNaturalist records exist as of 2026, confirming how rarely this fish is encountered outside its native river.
Within the genus Chaetostoma, males develop conspicuous interopercular odontodes that are displayed and used in competition for territories around preferred spawning sites — typically crevices or sheltered hollows within the rocky substrate of fast-flowing reaches. Males are presumed territorial around breeding sites and exhibit the bristle-cheek displays characteristic of the genus during encounters with rival males or when courting females.
Breeding
No breeding data for Chaetostoma stroumpoulos have been published. The species has not been documented in captivity, and its Endangered status and remoteness make collection and study difficult.
Chaetostoma in general are presumed cave or crevice spawners consistent with the broader loricariid pattern — the male occupies a sheltered rock crevice or under-boulder space and guards the egg clutch. Whether captive breeding has been achieved for any Huallaga River Chaetostoma species is not recorded in accessible sources.
In the aquarium
Chaetostoma stroumpoulos has not entered the ornamental trade and is, in practice, unavailable to aquarists. No hobbyist records have been located for this species. Given its Endangered status and the sensitivity of its single known locality, collection for the trade would be inappropriate and potentially illegal under Peruvian regulations applicable to threatened native fauna.
For completeness, the husbandry requirements of Chaetostoma from comparable sub-Andean rivers can be outlined: well-oxygenated, clean, moderately cool water (approximately 68–77 °F) with good flow, a rocky aquascape offering multiple attachment surfaces, and a diet based on algae, spirulina-rich prepared foods, and occasional blanched vegetable matter. Chaetostoma in general are peaceful with other species and make excellent additions to hillstream-style setups when legally and ethically sourced — but that description does not apply to C. stroumpoulos in its current conservation state.
Conservation
Chaetostoma stroumpoulos is listed as Endangered (EN) on the IUCN Red List, assessed in April 2014 and published in 2016 (IUCN 2016-1). The assessment was led by Hernán Ortega, Lisveth Valenzuela, Jessica Espino, Luisa Chocano, and Max H. Hidalgo of the National University of San Marcos, Peru.
The listing is based on criterion B1ab(iii,v): a restricted extent of occurrence (EOO approximately 211 mi²) combined with observed and projected decline in the quality of its habitat and in the number of mature individuals. The species is assumed to occur at four locations — the main Huallaga channel near Tingo María plus three tributary sites — a very small number that amplifies its vulnerability.
Threats identified in the IUCN assessment are substantial and intersecting. Dam construction in the Huallaga catchment poses the most systemic risk, with the potential to alter flow regime, sedimentation, and connectivity. Pollution from artisanal and small-scale mining introduces heavy metals and sediment that degrade the clean rocky substrates on which Chaetostoma depend. Agricultural runoff — particularly from coca cultivation in the Tingo María zone — contributes nutrient loading, herbicide contamination, and increased erosion. Taken together, these pressures represent an ongoing and plausible decline in both habitat quality and population size in what is already an extremely restricted range. No recovery plan or targeted conservation action specific to this species is known to be in place.