Taxonomy & naming
Psectrogaster ciliata was described by the German naturalists Johannes Müller and Franz Hermann Troschel in 1844. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) lists it as a valid species in the genus Psectrogaster, within the family Curimatidae — a large Neotropical family of small, laterally compressed, algae- and detritus-feeding characins closely related to the Prochilodontidae (the flannelmouth characins) and, more distantly, to the piranhas and pacus of Serrasalmidae, all within the order Characiformes.
Curimatids as a group are taxonomically difficult, with a long history of species being shuffled between genera on the basis of subtle differences in mouth position, dentition (or its near-absence) and scale counts; Psectrogaster is one of several genera erected to sort this diversity. This article keeps the genus as given, Psectrogaster, consistent with current Catalog of Fishes usage.
Morphology
Psectrogaster ciliata is a small, compressed, silvery fish typical of the curimatid body plan: a fairly deep, laterally flattened profile, a small subterminal or inferior mouth suited to grazing rather than seizing prey, and fine, closely set scales that give the flanks a bright, reflective sheen. Like other curimatids it lacks the conspicuous teeth of predatory characins — the family feeds using pharyngeal structures and a scraping, sediment-sifting mouth rather than an oral bite.
FishBase records a maximum size of 5 in standard length for the species, making it one of the smaller members of its family and genus. There is no documented external difference between the sexes beyond the general expectation, typical of the family, that ripe females run fuller-bodied ahead of the spawning migration.
Habitat
The species has a wide Neotropical range, recorded from the Essequibo, Orinoco, Rio Branco and Amazon basins of South America, with additional records from Argentina extending its known distribution into the southern part of the continent. Across this range it is a benthopelagic fish of tropical freshwater river systems, associating with the main channels and floodplains typical of large lowland Amazonian and Guianan drainages.
As with many curimatids, Psectrogaster ciliata is a migratory species, moving within river systems in step with the seasonal flood cycle — a pattern tied closely to its feeding ecology and reproduction. Specific water chemistry data (temperature, pH, hardness) were not captured for this species in the sources reviewed here; it can be assumed to share the broadly warm, lowland-tropical river conditions typical of its basins, but that should not be treated as a confirmed figure.
Feeding
Psectrogaster ciliata is a detritivore and aufwuchs grazer, feeding on the fine organic mud, algae and biofilm layer that coats submerged surfaces and river-bottom sediment — the classic curimatid feeding mode, and a sharp contrast to the predatory or omnivorous diets of many other characins covered in this atlas. This diet places it, ecologically, alongside other detritus- and algae-grazing Neotropical characins such as the larger Prochilodus rather than with the piranhas or silver dollars.
Because the species is not established in the aquarium trade, there is no hobbyist feeding record to draw on; any aquarium diet would need to replicate a detritivore's needs — fine sinking foods, algae wafers and biofilm-rich substrate — rather than the flake, pellet or meat diets typical of predatory or true omnivorous characins.
Mating
FishBase records that Psectrogaster ciliata reaches first spawning within its first year of life, at a size of roughly 6.5 in total length. Beyond that benchmark, detailed courtship behaviour has not been documented in the sources available for this species — curimatids as a family are known chiefly for undertaking spawning migrations timed to the seasonal flood pulse, moving from main river channels toward floodplain or headwater areas to spawn, rather than for any elaborate pairing display.
No external sexual dimorphism is documented for this species in the available sources; data is sparse.
Breeding
Psectrogaster ciliata does not spawn in captivity and does not respond to induced (hormone-based) spawning techniques, per FishBase — placing it alongside the migratory food-fish characins of this atlas (such as Prochilodus and Semaprochilodus) that rely on long-distance river migration and flood-pulse cues as reproductive triggers that cannot be replicated in captivity, rather than being an aquarium-breedable species. It should not be confused with the substrate-nesting true piranhas or the egg-scattering silver dollars covered elsewhere in this atlas; this species' natural spawning migration has not been captured in enough detail from available sources to describe further, and its reproduction is effectively unknown outside its wild river-and-floodplain setting.
Given the lack of any captive-breeding record, hobbyists should not expect to breed this species in a home aquarium, and no aquarium-conditioning protocol exists for it.
In the aquarium
Psectrogaster ciliata is not established in the aquarium hobby and is essentially unknown as a home aquarium fish — it appears in the sources reviewed here only through fisheries and taxonomic literature (FishBase, GBIF, the Catalog of Fishes), not hobbyist or retail sources. At a modest maximum size of 5 in SL it would, in principle, suit a mid-sized community setup for a peaceful, schooling detritivore, but no verified husbandry data — tank size, water parameters, feeding regime or compatible tankmates — exists to responsibly recommend care conditions.
Prospective keepers should treat this species as effectively unavailable in the trade and, if it were ever encountered, should default to the general curimatid template: a real school, sinking algae- and detritus-based foods, and warm, well-oxygenated, current-bearing water typical of its river habitat — while recognising that this is an inference from family-level biology, not a documented care record for the species itself.
Conservation
Psectrogaster ciliata has not been assessed by the IUCN Red List and currently carries a status of Not Evaluated. This is unsurprising for a small, wide-ranging, non-commercial curimatid — species like this typically fall outside the resources of periodic Red List assessment unless a specific threat or range-restriction prompts a review.
Its broad distribution across the Essequibo, Orinoco, Branco and Amazon basins, with an additional record from Argentina, suggests a wide range rather than a narrow endemic, but that alone is not a substitute for a formal conservation assessment. As with many Amazonian and Guianan basin fishes, the general long-term pressures on the region — damming, deforestation-driven sedimentation and water-quality change — are relevant background even though no species-specific conservation concern has been documented for it.