Taxonomy & naming
Dupouyichthys sapito was described by the American ichthyologist Leonard P. Schultz in 1944. It is the sole species in the genus Dupouyichthys, placed in the family Aspredinidae, the banjo catfishes, within the order Siluriformes.
The species has not been shuffled through other genera in the way many catfishes have — Dupouyichthys has stood as a monotypic genus since its description, distinguished from related banjo catfishes by details of its bony head ornamentation and by having only one set of paired plates in front of the anal fin, rather than the two sets typical of close relatives. The Catalog of Fishes treats Dupouyichthys sapito as the valid name.
Morphology
Like other banjo catfishes, Dupouyichthys sapito has the family's signature shape: a broad, flattened, bony head tapering into a slender, almost tadpole-like body and tail, an outline that gives the family its common name. The skin is scaleless (naked), a trait shared across catfishes that has direct implications for medication sensitivity.
This is an exceptionally small species — the maximum recorded size is only about 1 in standard length (1 in), making it one of the smallest banjo catfishes known. Its bony skull ornamentation is reported to be better developed than in some of its relatives, a detail used to help distinguish the genus. As in most Aspredinidae, the fish carries stiffened pectoral spines; these should be treated with the same care given to other catfish spines even though this species is diminutive.
Habitat
Dupouyichthys sapito is native to northern South America, recorded from the Magdalena River basin and the Lake Maracaibo basin, spanning parts of Colombia and Venezuela. It is a demersal fish, living on or near the bottom.
It is associated with river banks with vegetation, where its flattened shape and cryptic colouration let it hide among roots, leaf litter and marginal plant growth, or bury into fine substrate — a typical strategy for small banjo catfishes avoiding predators and strong current. Detailed water-chemistry data for the species has not been documented in the sources consulted; it inhabits the warm, lowland freshwaters typical of the Magdalena and Maracaibo drainages.
Feeding
Specific dietary studies for Dupouyichthys sapito are not available in the sources consulted. Banjo catfishes as a family are nocturnal benthic omnivores and micro-predators, foraging over or in the substrate after dark for small invertebrates and organic material, and this species' secretive, sand-associated habits are consistent with that general pattern.
In the rare event this species is kept, sinking foods offered after lights-out would suit its presumed nocturnal, bottom-foraging habits, following the pattern documented for its relatives rather than direct observation of this species.
Mating
Courtship and spawning behaviour have not been documented for Dupouyichthys sapito. Breeding biology in Aspredinidae generally is little studied, and this tiny, secretive river-bank species has not been the subject of detailed reproductive research in the sources consulted.
Breeding
Breeding is essentially unknown in the aquarium and poorly documented in the wild for this species. In several banjo catfishes, females carry the fertilised eggs attached to the belly skin via fleshy stalks until they hatch — a distinctive strategy known in some Aspredinidae — but this has not been confirmed specifically for Dupouyichthys sapito, so it should be taken as a family-level pattern rather than a documented fact for this species.
Given its rarity in the hobby and the sparse literature, no aquarium spawning of Dupouyichthys sapito is known to have been recorded. Honest reporting here means noting what is unknown rather than assuming any particular mode.
In the aquarium
Dupouyichthys sapito is not an established aquarium fish — it is rarely if ever seen in the trade, and this profile is compiled from taxonomic and distributional sources rather than aquarist experience. Should it appear, its tiny adult size (around 1 in SL) means it would not need a large tank, but it would still need a soft, fine substrate to bury into and plenty of cover such as roots and leaf litter to mimic its vegetated river-bank habitat.
As with all catfishes, its scaleless skin makes it sensitive to copper-based and many other medications, so any treatment should be dosed conservatively. Its small pectoral spines can still catch in netting, so moving the fish in a container rather than a net is the safer approach. Because so little is documented about its husbandry, anyone attempting to keep this species should proceed cautiously and be prepared for a knowledge gap rather than an established care sheet.
Conservation
The IUCN Red List assesses Dupouyichthys sapito as Least Concern, with the assessment dated 15 January 2021. FishBase also reports it as having low vulnerability to fishing pressure.
As a small, non-commercial species restricted to the Magdalena and Lake Maracaibo basins, it is not targeted by fisheries and there is no indication of significant population decline in the sources consulted. Its status is nonetheless tied to the health of these river systems, both of which face broader pressures from habitat modification and pollution across their range.