Taxonomy & naming
Parotocinclus prata was described by Ribeiro, Melo and Pereira in 2002, in Ichthyological Exploration of Freshwaters (volume 13, number 3, p. 218, Fig. 1). The type locality lies in the headwaters of the Rio da Prata, a stream tributary of the Ribeirão Quirico in the Rio São Francisco basin, in the municipality of Presidente Olegário (Fazenda São Zeferino, near Galena), at approximately 18°22′S, 46°14.3′W, Minas Gerais State, Brazil. No synonyms are recorded, and the name is treated as valid by the Catalog of Fishes (Eschmeyer, CAS).
The species belongs to the subfamily Hypoptopomatinae. As with all members of the genus, Parotocinclus prata is distinguished from the closely similar Otocinclus by the presence of an adipose fin, which Otocinclus lacks.
Morphology
Parotocinclus prata is a small loricariid recorded at about 1.5 in in standard length, with the flattened body and ventral suckermouth characteristic of the dwarf hypoptopomatines. It bears the adipose fin diagnostic of the genus. Published data on live coloration and sexual dimorphism beyond the original description are not available.
Habitat
The species is known from the headwaters of the Rio da Prata, within the upper Rio São Francisco basin in Minas Gerais, southeastern Brazil. The type material came from a small stream tributary system. Small hypoptopomatines of these highland headwaters are generally associated with clear, flowing, well-oxygenated water where they graze firm surfaces, but no specific water-chemistry or microhabitat measurements have been published for P. prata.
Feeding
No dietary study has been published for Parotocinclus prata. By analogy with other small Parotocinclus, it is presumed to graze aufwuchs — the algal and microbial film on rocks, wood and plant surfaces — but no gut-content or feeding-behaviour data are available.
Mating
No data on courtship or mating behaviour have been published for this species.
Breeding
No breeding report exists for Parotocinclus prata, in the wild or in captivity. Reproductive mode, clutch size and parental care are undocumented.
In the aquarium
Parotocinclus prata has no meaningful aquarium history and is not part of the ornamental trade. No husbandry guidance specific to the species has been published. It is recorded here as a described taxon rather than a hobby fish.
Conservation
The IUCN Red List assessed Parotocinclus prata as Least Concern, last assessed in 2018. As a small fish restricted to headwaters of the upper Rio São Francisco basin, its prospects depend on the integrity of those streams; no species-specific population decline has been documented.