Taxonomy & naming
Apareiodon vladii was described by the Brazilian ichthyologist Carla Simone Pavanelli in 2006, one of many species-level descriptions that have expanded the genus Apareiodon over the past few decades. The species epithet honours Vladimir Pavan Margarido, a Brazilian biologist. It belongs to the family Parodontidae — commonly called the scrapetooths or parodontids — a small Neotropical family of streamlined, bottom-oriented characins distinguished by a specialised, downturned mouth and premaxillary teeth adapted for scraping algae and biofilm from hard surfaces, entirely distinct from the deep-bodied, large-jawed lineages of Serrasalmidae that give this broader group its "piranha" reputation.
Within the genus, FishBase notes that A. vladii is distinguished from its close relative A. piracicabae by a pointed premaxillary bone bearing the largest median cusp, by having a single maxillary tooth rather than two, and by a longer anal-fin ratio — the kind of fine dental and fin-count detail typical of how Apareiodon species are told apart, since many are superficially similar small silvery grazers. As with much of the genus, the Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the reference point for the currently valid combination, and no synonymy or name change affecting this species is noted in the cached sources.
Morphology
Apareiodon vladii is a small fish, with FishBase recording a maximum published length of 4.5 in standard length — modest even by the standards of the minor characins, and far short of the pacus and predatory characins elsewhere in this family grouping. Like other parodontids it has a slender, fusiform (torpedo-shaped) body built for holding position in flowing water, and the family's signature feature is its mouth: a ventrally positioned, scraper-adapted jaw with specialised premaxillary and maxillary teeth suited to rasping algae and biofilm from rock and wood rather than gripping prey.
The cached sources do not describe colouration or fin pattern for this species in detail, and no photographs or field descriptions of live colouration were found in the available research. Data on that front is sparse and should not be guessed at.
Habitat
The species is known from the Piquiri River, a tributary system within the upper Paraná River basin in Brazil, where it occupies flowing, tropical freshwater. FishBase classifies it as benthopelagic, consistent with a fish that spends much of its time close to the streambed and submerged structure where its grazing habit is put to use, rather than roaming open water.
Specific water chemistry data (temperature range, pH, hardness) for A. vladii itself was not found in the cached sources. Related Parodontidae, including congener Apareiodon affinis, are documented from river systems across the broader Río de la Plata basin spanning Brazil, Paraguay and Argentina, an area that includes both tropical and subtropical, seasonally cooler stream conditions — but that is evidence about the genus and family in general, not a confirmed reading for this specific species, and is presented here only as context.
Feeding
Parodontidae as a family are algae-grazers and detritus-feeders, and a study of the diet and digestive tract of the related species Apareiodon affinis found it to be detritivorous, consistent with that family-wide pattern. No species-specific dietary study of A. vladii was found in the cached sources, but its scraper-type dentition — the same premaxillary and maxillary tooth arrangement used to distinguish it from A. piracicabae — points to the same general feeding strategy: rasping algae, biofilm and organic detritus from submerged rock, wood and other hard surfaces in flowing water, rather than taking large prey items or plant matter by tearing.
No aquarium feeding data for this species was found. Given the family pattern, a diet built around grazing-friendly foods — algae wafers, blanched vegetables, and biofilm-rich tank surfaces — would be the reasonable expectation, but this is inference from family biology rather than a documented account of A. vladii itself.
Mating
No courtship or pairing behaviour has been documented for Apareiodon vladii in the cached sources. No external sexual dimorphism is described either. This is a genuine gap in the available literature rather than an oversight in this account — small, single-river Parodontidae species like this one are rarely the subject of the kind of aquaculture or aquarium-trade attention that generates courtship observations.
Breeding
There is no documented breeding record for Apareiodon vladii, in the wild or in captivity, in any of the cached sources. The species does not appear to be established in the aquarium trade, and nothing about spawning mode, egg type, or parental care can be stated with confidence. Rather than default to a generic egg-scattering assumption, this account leaves breeding as unknown pending better data — a fair and honest position for a narrow-range stream fish that has attracted essentially no hobbyist or aquaculture attention since its 2006 description.
In the aquarium
Apareiodon vladii is not a species kept or traded in the aquarium hobby as far as the cached research shows — no husbandry accounts, tank-size recommendations or stocking guidance were found. Its small adult size (around 4.5 in SL) and its flowing-water, grazing-scraper biology as a parodontid suggest it would, in principle, suit a well-oxygenated, current-driven setup with hard surfaces to graze rather than a still, planted community tank, but this is a reasonable inference from its family and habitat, not a tested aquarium account.
Prospective keepers should treat this species as effectively unavailable and undocumented in captivity. If it is ever encountered in the trade, water conditions matching its native flowing, tropical Piquiri River habitat and a diet built around grazing foods would be the sensible starting point, informed by general Parodontidae care rather than any species-specific record.
Conservation
Apareiodon vladii has not been evaluated by the IUCN Red List — its status is Not Evaluated. That is common for narrow-range, single-basin Parodontidae described in the last two decades, many of which have not been assessed at all despite being restricted to specific river systems where localised threats (damming, sedimentation, water-quality change) could matter disproportionately to a small population.
No population trend, threat assessment or trade-pressure data was found for this species in the cached sources. Its known range in the Piquiri River, a tributary of the upper Paraná basin — a heavily dammed and agriculturally developed system — is the kind of setting where habitat pressure on small-range endemics is a plausible long-term concern, but that connection is not established by any source found here and should not be overstated.