Taxonomy & naming
Rhinotocinclus discolor was described by Roberto E. Reis and Pablo Lehmann A. in 2022, in Neotropical Ichthyology (volume 20, number 2, article e220002), within the paper 'A new genus of armored catfish (Siluriformes: Loricariidae) from the Greater Amazon, with a review of the species and description of five new species.' That work erected the genus Rhinotocinclus to accommodate a group of small Hypoptopomatinae previously scattered across Parotocinclus and related genera, and named five new species in the process — of which R. discolor is one.
The genus name combines the Greek rhinos (snout) with the established genus name Otocinclus, a reference to the conspicuous, elegant snout that distinguishes these fishes. The Catalog of Fishes (Eschmeyer, CAS) recognises Rhinotocinclus discolor Reis & Lehmann, 2022 as the valid name. The species sits within subfamily Hypoptopomatinae, the dwarf suckermouth catfishes, in the family Loricariidae.
The meaning of the specific epithet discolor is not stated in the cached source and is not reproduced here to avoid invention.
Morphology
Rhinotocinclus discolor is a very small loricariid, reaching about 1 in standard length — the largest measured specimen was 1 in SL. It carries the bony dermal armour typical of the family and the relatively elongate, projecting snout that gives the genus its name. Detailed counts, colour-in-life description, and diagnostic characters separating it from its congeners are given in the original description (Reis & Lehmann, 2022); beyond the size figure, no further morphological detail is reproduced in the cached source, and none is invented here.
No data on sexual dimorphism in this species has been published.
Habitat
The species is recorded from South America — specifically Venezuela — where it has been collected from creeks. It is a freshwater, demersal (bottom-associated) fish of tropical waters. No published temperature, pH, hardness, or depth measurements for its habitat are available in the cached source, so none are stated here.
Feeding
No feeding study specific to Rhinotocinclus discolor has been published. Members of subfamily Hypoptopomatinae are characteristically aufwuchs grazers, rasping algae, biofilm, and fine detritus from submerged surfaces, and the species sits at a low trophic level (approximately 2.6) consistent with that diet. Direct dietary observations for this species are not on record.
Mating
No data on the courtship or mating behaviour of Rhinotocinclus discolor has been published.
Breeding
No data on the reproduction, spawning mode, clutch size, or parental care of Rhinotocinclus discolor has been published. The species is not known to have been bred in captivity.
In the aquarium
Rhinotocinclus discolor is not established in the aquarium hobby, and no documented husbandry exists for it. As a recently described dwarf creek-dwelling Hypoptopomatinae, any keeping would by analogy with related small suckermouths call for clean, well-oxygenated water, gentle current, soft substrate, and abundant grazing surfaces — but these are general expectations for the group, not parameters recorded for this species. No verified aquarium care information is available.
Conservation
Rhinotocinclus discolor has not been evaluated by the IUCN Red List. As a species described only in 2022 and known from a limited collection in Venezuelan creeks, its distribution, population size, and any threats are essentially undocumented. No conservation assessment can be made from the available data.