Taxonomy & naming
Potamorhina squamoralevis was described by Braga & Azpelicueta in 1983. It belongs to the family Curimatidae — the toothless characins, a large Neotropical family of detritivorous and algivorous fishes within the order Characiformes — and to the genus Potamorhina, a group of laterally compressed, silver river characins found across the Amazon, Orinoco and Paraguay-Paraná drainages. Curimatidae is part of the broader characin radiation covered by this atlas alongside Hemiodontidae, Prochilodontidae and the true piranha/pacu family Serrasalmidae, and like many of its relatives it is a grazer rather than a predator, lacking the jaw teeth of the fish most people picture when they hear "characin."
As with much of the smaller-bodied Curimatidae, published taxonomic literature on this specific species is limited outside the original description and subsequent distribution notes; a 2015 academic paper documented a range extension into Uruguay, confirming the species within the Paraguay-Paraná system beyond its originally described range. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is treated here as the authority for the valid combination Potamorhina squamoralevis; no genus reassignment is reflected in the sources consulted for this article.
Morphology
Potamorhina squamoralevis is a laterally compressed, silvery river characin typical of the genus — a streamlined, moderately deep-bodied fish built for schooling in open water rather than for ambush or ground-hugging. FishBase records a maximum published size of 9 in standard length, placing it among the mid-sized minor characins: distinctly larger than a small tetra but far short of the size reached by its migratory Prochilodus and Semaprochilodus relatives, let alone the giant pacus of Serrasalmidae.
Detailed morphological description — fin ray counts, mouth structure, and colour pattern beyond the general silver Curimatidae body plan — is not available in the sources reviewed for this article. Data sparse; specific field marks distinguishing this species from congeners are not documented here.
Habitat
The species is documented from the Paraguay and Paraná River basins of South America, a large subtropical river system draining parts of Brazil, Paraguay, Bolivia and Argentina, with a confirmed range extension into Uruguay reported in the academic literature. FishBase classifies it as a freshwater, benthopelagic species under a temperate climate classification — consistent with the cooler seasonal swings the southern Paraná system experiences relative to the tropical Amazon, and a reminder that not every South American characin comes from warm blackwater.
A Brazilian research study recorded the species as abundant in the Pantanal wetland (Baía Tuiuiú, Mato Grosso do Sul), a vast seasonally flooded lowland within the upper Paraguay basin — consistent with the floodplain, benthopelagic habits typical of Potamorhina and its Curimatidae relatives, which forage over soft sediment in slow-moving river channels, lagoons and flooded margins. Detailed temperature and pH figures are not documented in the sources reviewed; keepers and researchers should treat the Paraguay-Paraná basin's generally subtropical, seasonally variable conditions as the working context rather than assuming the warm, soft blackwater typical of Amazon tributaries.
Feeding
A Brazilian study specifically examined the diet of Potamorhina squamoralevis in the Pantanal (Baía Tuiuiú, Mato Grosso do Sul), consistent with the genus's general reputation as a detritus- and biofilm-grazing minor characin. Like other Curimatidae, Potamorhina species are toothless as adults and feed by sifting fine organic sediment, algae and biofilm from the substrate rather than pursuing prey, placing this species firmly in the detritivore/omnivore camp shared by hemiodus, curimatas and Prochilodus rather than the predatory end of the characin spectrum occupied by Brycon or the golden dorado.
The specific findings of the Pantanal diet study — proportions of detritus, algae, invertebrates or plant material — were not accessible in the source reviewed for this article beyond its title and abstract-level indication of feeding ecology research; data sparse on the precise dietary breakdown.
Mating
No courtship or pairing behaviour for Potamorhina squamoralevis is documented in the sources reviewed for this article. Data sparse — nothing here should be assumed by analogy with better-studied relatives without direct confirmation.
Breeding
No spawning mode, parental care, or aquarium/aquaculture breeding record for Potamorhina squamoralevis is documented in the sources reviewed for this article. This is consistent with the pattern across much of Curimatidae: many of the family's smaller, non-commercial species are simply not bred in captivity and go unrecorded in the aquaculture literature, unlike their much larger, farmed Prochilodus and Semaprochilodus relatives, which are hormone-induced, commercially bred migrators. Whether P. squamoralevis follows the open-water egg-scattering pattern typical of many Curimatidae or something else is not confirmed here — data sparse, and no breeding mode is asserted.
In the aquarium
Potamorhina squamoralevis does not appear to have an established aquarium-keeping history in the sources reviewed for this article — no hobby care guides, forum accounts, or trade records were found. What can be said with confidence from its documented biology: at a maximum of roughly 9 in SL it is a mid-sized fish that would need a substantial, long aquarium if ever kept, it is a grazing detritivore rather than a predator so it poses no fin-nipping or predation risk to tankmates its own size, and as a schooling river characin it would be expected to want the company of its own kind rather than solitary housing.
Those expectations are inferred from its family and genus rather than from any documented aquarium record, and prospective keepers should treat this species as essentially unavailable and unstudied in the hobby rather than assume any specific husbandry protocol works for it.
Conservation
The IUCN Red List assessment cited via FishBase places Potamorhina squamoralevis in the Least Concern category, dated 24 June 2020. This reflects a species with a documented range spanning the Paraguay and Paraná basins across multiple countries, plus a confirmed extension into Uruguay, and no indication in the sources reviewed of significant population decline or targeted fishing pressure specific to this species.
As with much of the Paraguay-Paraná basin's fish fauna, the general long-term pressures on the system — damming, water management, agricultural runoff and habitat modification in the Pantanal and surrounding floodplain — are relevant background context even though this species itself is not currently flagged as threatened. No dedicated conservation programme or trade-driven collection pressure for this species is documented here.