Taxonomy & naming
Sturisoma monopelte was described by Henry Weed Fowler in 1914, based on material from Guyana. The description appeared in Fowler's work on South American fishes; the name was published without parentheses because Fowler placed it directly in Sturisoma, and it has remained there without a genus change — hence the authority is written without parentheses as Fowler, 1914. The Catalog of Fishes (Eschmeyer, CAS; updated 10 June 2026) confirms: valid as Sturisoma monopelte Fowler, 1914 (CoF species record 5427).
The taxonomic status of the species relative to the genus Sturisomatichthys was clarified by Londoño-Burbano & Reis (2019) in their comprehensive taxonomic revision of Sturisomatichthys published in Copeia (107(4): 764–806). That study confirmed that S. monopelte belongs to Sturisoma sensu stricto, not to Sturisomatichthys Isbrücker & Nijssen, 1979 — a distinction based on morphological characters including the number of mid-dorsal plate rows, the shape of the rostrum, and the configuration of the caudal fin rays. The IUCN assessment (Ballen 2023) also references Londoño-Burbano & Reis (2019) for the geographic range description, further confirming the placement.
Sturisoma belongs within Loricariinae. The genus as currently understood includes species distributed from Colombia and Venezuela south through the Guiana Shield into central Amazonian Brazil. S. monopelte carries no aquarium L-number.
Morphology
Sturisoma monopelte is a slender, moderately depressed whiptail catfish. FishBase (Ferraris 2003) records a maximum length of 10.5 in for unsexed specimens, without specifying whether this is standard length or total length; the IUCN assessment notes no SL qualifier, so this figure likely represents total length including the caudal filament typical of Sturisoma. Adult body length without the filament is considerably shorter.
The genus Sturisoma is characterised by an elongated, torpedo-like body that narrows progressively toward the tail, a well-developed rostral shield on the snout, and a caudal filament that can extend well beyond the tail fin proper. The armour consists of overlapping bony scutes arranged in the standard loricariid pattern, with the ventral surface of the body bearing a largely unplated or more lightly plated area. The mouth is ventral and adapted for biofilm-scraping.
The genus name derives from the German Stör (sturgeon) and the Greek soma (body), reflecting the superficially sturgeon-like profile of the elongated body and prominent snout. Published coloration descriptions for S. monopelte specifically are limited, but the species is expected to show the typical Sturisoma pattern of brownish or tan ground colour with scattered darker spots or a mid-lateral stripe, pale underside, and finely spotted or transparent fins.
As in other Sturisoma species, facultative air-breathing has been recorded for the genus (FishBase, Ref. 126274) — an adaptation of potential significance in shallow, seasonally variable water bodies where dissolved oxygen may fluctuate.
Habitat
The species is distributed across the Guiana Shield and is known from the lower Amazon in Brazil. The IUCN assessment (Ballen 2023) describes the range as widespread on the Guiana Shield, with occurrences in Guyana and in the Brazilian state of Amapá; Londoño-Burbano & Reis (2019) provide the definitive range description. FishBase lists the type locality drainage as the Rupununi River basin (a major tributary of the upper Essequibo in southwestern Guyana) and the lower Amazon.
The Rupununi River and the rivers of the Guiana Shield are predominantly clearwater systems — well-oxygenated, relatively low in suspended sediment, and with moderate conductivity compared to the extreme blackwater of the Negro basin. The lower Amazon occurrences suggest the species also tolerates the vast, seasonally inundated floodplain environment of the main Amazon channel and its tributaries.
Water temperatures in these equatorial systems typically range from 75–84 °F. pH varies — clearwater rivers of the Guiana Shield tend toward neutral to mildly acidic (pH 5.5–7.5). The IUCN notes an extent of occurrence of 185,352 mi² and area of occupancy of 15,283 mi², and museum records suggest it is not locally rare (lots of up to 30 individuals are known).
Feeding
Specific dietary data for Sturisoma monopelte are not available in the published literature. By analogy with well-studied Sturisoma species — particularly the widely kept S. barbatum and S. aureum — the diet is expected to be primarily herbivore-detritivore: periphyton, algal biofilm, fine detritus, and diatoms scraped and sieved from smooth substrate surfaces (rocks, leaf litter, wood, sandy substrate).
The facultative air-breathing ability documented for the genus suggests the species is adapted to microhabitats where benthic oxygen concentration may be low at times, consistent with feeding in leaf-litter accumulations and fine-sediment substrate zones.
In aquaria housing related Sturisoma species, green algae on aquarium glass and decor is grazed continuously, supplemented with algae wafers, spirulina discs, blanched courgette and cucumber, and occasional soft vegetables. This dietary regime is appropriate as a starting point for S. monopelte. Protein foods (live or frozen invertebrates) can be offered as an occasional supplement but should not be a staple.
Mating
No published observations of courtship or mating behaviour specific to Sturisoma monopelte exist. The reproductive biology of the genus is best documented for the commonly kept S. barbatum, S. aureum, and S. festivum, and it is reasonable to assume S. monopelte follows broadly similar patterns — while recognising that differences between Sturisoma species exist.
In Sturisoma generally, breeding is triggered by environmental cues associated with the onset of the rainy season: a drop in temperature (36–39 °F), increased water flow, and slightly reduced pH or hardness. Males become territorial and defend a section of flat vertical surface — the glass wall, a flat rock, or a broad piece of driftwood. Females select males and deposit adhesive eggs on the chosen surface; the male then guards the clutch.
For S. monopelte, the clearwater river environment of the Guiana Shield suggests conditioning water should be moderately soft and slightly acidic to neutral (pH 6.0–7.2, TDS 100–300 µS/cm). Slight temperature drops and increased current simulate seasonal onset and may help initiate spawning in a well-conditioned pair.
Breeding
Sturisoma monopelte is not established in the aquarium hobby, and captive breeding accounts appear to be absent from the accessible hobbyist literature. The species carries no L-number and is not regularly imported. Any breeding observations would constitute original data.
For the related and commonly bred species such as S. barbatum and S. panamense, aquarists report the following pattern applicable to the genus: eggs are deposited in a neat cluster on a vertical flat surface (typically glass or slate); the clutch is pale green to yellowish, turning grey-brown as development proceeds; paternal care involves the male fanning and cleaning the eggs for an incubation period of roughly 7–10 days at 79 °F; fry are large relative to the egg size, mobile immediately after hatching, and begin grazing on biofilm and fine algae within days. This profile provides a reasonable baseline for working with S. monopelte.
Conditioning should emphasise high-quality varied vegetable foods, clean well-oxygenated water, and a gradual seasonal simulation (modest temperature reduction of 36–37 °F, increased flow, slight water softening) to trigger spawning.
In the aquarium
Sturisoma monopelte is essentially absent from the aquarium trade. No L-number has been assigned, and the species does not appear in standard import lists for European or North American hobbyists. It may occasionally surface as a by-catch in imports of Sturisoma species from Guyanese or Brazilian collections, but this would be unusual.
Hobbyists familiar with S. barbatum or S. panamense will find the general Sturisoma husbandry template a useful starting point. A tank of at least 30 US gal with a long footprint accommodates the 10.5 in adult size. Water should be clean, well-oxygenated, and moderately soft to moderately hard (pH 6.0–7.5, temperature 75–82 °F). A moderate current from a powerhead or overflow return, a sand substrate, smooth flat rocks, and pieces of driftwood provide an appropriate biotope. Plants are generally safe with Sturisoma species, which are primarily biofilm grazers rather than leaf-eaters.
The facultative air-breathing ability of the genus means the fish will occasionally surface to gulp air; ensure the water surface is not completely sealed by a tight-fitting lid. A small gap for air access is sufficient.
Tankmates should be peaceful species tolerant of similar water conditions — South American tetras, hatchetfishes, pencilfish, and small Corydoras species are all compatible. The elongated caudal filament of adult males is vulnerable to fin-nipping, so avoid boisterous or nippy species.
Conservation
The IUCN Red List assessed Sturisoma monopelte as Least Concern in 2023 (assessment date 14 January 2021; assessor: Gustavo A. Ballen), based on a wide distribution across the Guiana Shield and lower Amazon, an EOO of 185,352 mi² and AOO of 15,283 mi², and the absence of known threats. Museum records indicating lots of up to 30 individuals suggest the species is not globally rare, despite the paucity of published field ecology.
No threats to the species are currently identified. The Guiana Shield in Guyana and Amapá, Brazil, is one of the world's better-preserved large river systems in terms of intact forest cover and minimal industrial development relative to the western Amazon, reducing the acute habitat threats that face many freshwater fish in Colombia, Peru, or the Brazilian cerrado.
The species is not subject to conservation measures, has no harvest management plan, and is not subject to international trade controls. No presence in protected areas is recorded. As with all freshwater fish on the Guiana Shield, long-term threats from artisanal gold mining (which causes mercury contamination and habitat disturbance in Guyanese and Brazilian rivers) and potential future hydropower development in the shield are worth monitoring, even if they represent no current quantified risk to this species.