Taxonomy & naming
Parotocinclus minutus was described by Julio César Garavello in 1977. The Catalog of Fishes (Eschmeyer, CAS) recognises it as a valid species in the genus Parotocinclus (species id 5314). It is placed in the subfamily Hypoptopomatinae, the group of small dwarf suckermouth catfishes that includes the popular otocinclus and their close relatives.
The genus Parotocinclus has long been recognised as a taxonomically difficult assemblage, and several authors have questioned its monophyly. For the purposes of this atlas the name follows the Catalog of Fishes, which continues to list Parotocinclus minutus Garavello, 1977 as valid. FishBase's principal reference for the species is Burgess (1989), An Atlas of Freshwater and Marine Catfishes.
Morphology
Parotocinclus minutus is a very small loricariid, reaching a maximum of about 1.5 in standard length. As in other hypoptopomatines, the body is clad in rows of bony lateral plates and the mouth is a ventral sucker disc adapted for clinging to surfaces and rasping the thin biofilm that coats them.
Detailed morphological diagnostics beyond the size figure are not reproduced in the source consulted here. No data on coloration in life, fin counts, or distinguishing features were available in the cache, so no further description is offered rather than risk fabrication.
Habitat
The species is endemic to the Vasa-Barris River basin in northeastern Brazil. The available data characterise it simply as a freshwater, demersal, tropical fish — that is, a bottom-associated species of warm inland waters.
No published microhabitat detail (substrate, current, water chemistry, or seasonal regime) was available in the source consulted, so specific habitat parameters are left unstated. Members of the genus are typically found clinging to rocks, submerged roots and leaf litter in flowing streams, but site-specific data for this species were not on hand.
Feeding
Parotocinclus minutus is a grazer with an estimated trophic level of 2.4, consistent with the herbivore/detritivore feeding mode typical of the genus. In practice this means a diet dominated by aufwuchs — the film of algae, diatoms, microorganisms and fine detritus that grows on submerged surfaces — rasped from rocks and plant material with the ventral mouth.
Unlike the wood-eating Panaqolus and Panaque of the subfamily Hypostominae, hypoptopomatines such as this species are not xylophages; driftwood serves as grazing substrate rather than food. No aquarium feeding observations were available for this species specifically.
Mating
No data on courtship or mating behaviour have been published for Parotocinclus minutus. The species is known essentially from collected specimens, and its reproductive behaviour in the wild has not been described in the source consulted.
Breeding
No breeding data are available for Parotocinclus minutus. The species is not established in the aquarium hobby, and no spawning reports, egg counts, or details of parental care could be sourced. Small hypoptopomatines generally scatter adhesive eggs on plants and hard surfaces with little or no parental care, but this has not been confirmed for the present species.
In the aquarium
Husbandry data for Parotocinclus minutus are sparse to nonexistent; the species is essentially absent from the ornamental trade and is not a documented aquarium fish. No species-specific tank, water-parameter, or compatibility recommendations can be offered without inventing them.
By analogy with related dwarf suckermouths, such grazers would require mature, well-oxygenated water with established biofilm and gentle tankmates, but these are general expectations for the group rather than tested guidance for this species.
Conservation
The IUCN Red List assessed Parotocinclus minutus as Least Concern, in an assessment dated 7 November 2018. The Least Concern status reflects the absence of evidence for significant decline at the time of assessment rather than detailed population monitoring.
As a basin-restricted endemic of the Vasa-Barris drainage, the species' long-term prospects are nonetheless tied to the health of that river system; localized habitat alteration could affect narrowly distributed fishes of this kind. No species-specific threats were detailed in the source consulted.