Taxonomy & naming
Psalidodon correntinus was described by the Argentine naturalist Eduardo Ladislao Holmberg in 1891, based on material from the Río Paraná near the city of Corrientes in northeastern Argentina. The name correntinus references that type locality — a Latinised form of Corrientes. Holmberg's original description appeared in the Zoologische Abhandlungen (Dresden), and the species went essentially without fresh material for well over a century before Mirande and colleagues published a formal redescription in 2006, drawing on newly collected specimens from the same locality.
FishBase currently places the species under the generic name Psalidodon correntinus, reflecting a contested realignment of many South American Astyanax into the older genus Psalidodon Eigenmann, 1908. However, Eschmeyer's Catalog of Fishes — the primary authority for valid names used across this site — recognises Astyanax as the valid genus encompassing correntinus, and that placement is followed here. The taxonomic situation in South American characids is actively evolving, and readers consulting FishBase or regional checklists may encounter both names.
The species belongs to the family Characidae, the most speciose family of freshwater fishes in South America, and to the very large genus Astyanax, which spans virtually every major drainage on the continent and extends north through Central America.
This fish was long listed as Astyanax correntinus; Eschmeyer's Catalog of Fishes places the species in Psalidodon, and the current combination Psalidodon correntinus is followed here.
Morphology
Psalidodon correntinus is a benthopelagic, fusiform characid of typical Astyanax body plan: moderately deep-bodied, laterally compressed, with a forked tail and the adipose fin characteristic of the order Characiformes. The species is distinguished in part by a high anal fin ray count — FishBase records 45 anal soft rays — which places it among the higher-rayed members of the genus and was among the meristic characters examined in Mirande et al.'s 2006 redescription.
Detailed external colour pattern and precise size data are not recorded in the available sources. Like most mid-sized Astyanax the species is likely silver-bodied with a dark lateral stripe and a caudal spot, conforming to the ground-plan of the genus, but specific colouration should be confirmed from the primary literature. No common name has been established in the trade, reflecting its limited presence in the hobby.
Habitat
The species is restricted to freshwater habitats in the lower Paraná basin of northeastern Argentina, with confirmed records from Corrientes, Entre Ríos, and Santa Fé provinces. Its type locality is the Río Paraná near the city of Corrientes. The IUCN assessment notes that it occupies freshwater wetlands including permanent and seasonal rivers and marshes, and that within these systems it favours sandy-bottomed, slow-flowing waters with aquatic vegetation in the littoral zone.
The species' extent of occurrence is estimated at approximately 36,449 mi² and area of occupancy at 5,510 mi², figures that place it firmly within the lower Paraná floodplain. The Paraná is one of South America's major rivers, and its floodplain supports a diverse and seasonally dynamic fish assemblage; P. correntinus is part of the subtropical ichthyofauna that exploits marginal, vegetated habitats during high-water periods.
Feeding
No detailed dietary studies specific to Psalidodon correntinus appear in the available literature. FishBase assigns the species a trophic level of 3.0, which is consistent with omnivory — the guild-level default for Astyanax in the absence of stomach-content data. Most small Astyanax are opportunistic omnivores that take small invertebrates, plant material, algae, and terrestrial insects falling to the water surface, and this is the expected feeding strategy for P. correntinus given its habitat among littoral vegetation.
In an aquarium context the species would likely accept standard prepared foods — quality flake and small pellets — supplemented with frozen or live invertebrates. However, given how rarely this fish appears in the hobby, practical feeding observations from captive specimens are essentially absent from the record.
Mating
No species-specific observations on the mating behaviour of Psalidodon correntinus are recorded in the sources available. As a member of Astyanax, it would be expected to follow the characteristic characid pattern of egg-scattering with no pair bond formation and no parental care. Male Astyanax typically pursue females in open water or among vegetation, and spawning is initiated when a receptive female releases eggs that are simultaneously fertilised by the attending male or males.
In seasonally flooded systems like the Paraná floodplain, spawning in many characids is triggered by rising water levels and associated changes in temperature and photoperiod, with adults using the flooded littoral vegetation as spawning and nursery habitat. Whether P. correntinus follows this seasonal strategy or spawns more opportunistically is not documented.
Breeding
No captive breeding accounts are available for Psalidodon correntinus, and the species is not established in the ornamental-fish trade. By analogy with congeners and other small Characidae, the reproductive mode would be expected to involve broadcast egg-scattering over fine-leaved plants or substrate, with adhesive or semi-adhesive eggs and no parental care. Incubation and larval development times have not been reported for this species.
In the wild, reproduction likely occurs in the vegetated littoral margins of rivers and marshes during periods of appropriate flow and temperature. Fry would be expected to feed initially on zooplankton and small invertebrates in sheltered shallow-water nursery habitats — a pattern common across floodplain Astyanax of the Paraná-Plata system.
In the aquarium
Psalidodon correntinus is essentially absent from the ornamental-fish hobby and is not commercially available. Its subtropical origin — the lower Paraná basin — means it would tolerate cooler temperatures than most tropically kept tetras; an unheated or mildly heated aquarium in the range of 64–75 °F would likely suit it, though precise temperature tolerances have not been published.
For any aquarist who obtains the species through scientific collection or specialist exchange, the expected husbandry would follow the Astyanax template: a well-oxygenated tank with open swimming space and some fine-leaved planting, neutral to slightly alkaline water consistent with the Paraná system, and a varied omnivore diet. Given how little is documented about this fish in captivity, hobbyist observations would be a genuine contribution to knowledge of the species.
Conservation
Psalidodon correntinus is assessed as Least Concern (LC) on the IUCN Red List, with the assessment published in 2023 based on a November 2020 evaluation by Brancolini, Baigun, and Minotti. The assessment notes a reasonably wide distribution across three Argentine provinces, with no identified threats sufficient to trigger a threatened category. Population trend is listed as unknown.
Despite the overall Least Concern rating, the IUCN assessment identifies urban sewage pollution near Corrientes city — the species' type locality — as a localised threat. No formal conservation actions are currently in place for the species. Its EOO of approximately 36,449 mi² and AOO of 5,510 mi² suggest a geographically restricted range within the broader Paraná floodplain, and ongoing habitat pressures across the lower Paraná from agriculture, urban development, and hydrological modification warrant continued monitoring of the region's small-bodied characid fauna.