Piranhas & Pacus · Hemiodus & minor characins

Cyphocharax boiadeiro

Melo, 2017

IUCNNOT EVALUATED
NEnot on the EX–LC scale
CARESNOT LISTED
Scientific size2.5 in6.1 cm standard length
Depthnot recorded
DietLikely an omnivorous detritus- and biofilm-grazer typical of Curimatidae; not directly studied for this species, but the closely related congener Cyphocharax voga is ~96% detritivorous in diet studies
BreedingNot documented for this species — data sparse; do not assume open-water egg-scattering without direct evidence
Sexual dimorphismMinimalNo sexual dimorphism documented for this species in the sources reviewed
PhotographsSee photosGoogle Images →

Cyphocharax boiadeiro is a small, quiet grazer from the upper rio Araguaia in central Brazil, described in 2017 by Bruno F. Melo and placed in Curimatidae, the toothless "minor characin" family of detritus-sifting shoalers that also holds the much larger Prochilodus food fish. It has none of the drama of its piranha and pacu relatives in this atlas's broader group: FishBase records a maximum size of just 2.5 in standard length, and the species is best understood as an unassuming, silvery bottom-and-midwater grazer rather than a predator or a giant. It is essentially unknown in the aquarium trade, and this account is honest about how little has been published on it beyond the original taxonomic description.

What's in the name

Cyphocharax boiadeirosy-foh-KAR-ax boy-ah-DEH-ee-roh

Cyphocharax
  • kyphosGreekbent, humped — referring to the arched or humped dorsal body profile typical of the genus
  • charaxGreeka pointed stake or sharp fish — a common Greek-derived suffix used across characiform genus names
boiadeiro
  • boiadeiroPortuguesecattle driver/cowherd — a vernacular Brazilian Portuguese term used as the species epithet by Melo (2017); the specific reasoning behind the epithet was not detailed in the sources reviewed for this account

Taxonomy & naming

Cyphocharax boiadeiro was described by the Brazilian ichthyologist Bruno F. Melo in 2017, in a paper published in Zootaxa 4247(2):114-120 that established the species from the upper rio Araguaia drainage in central Brazil. It belongs to the genus Cyphocharax within the family Curimatidae — the curimatas, a large group of small, toothless, detritivorous characiforms distinct from the predatory piranhas (Serrasalmidae) and the migratory flannelmouth characins of the genus Prochilodus that also appear elsewhere in this atlas's broader "Piranhas & Pacus" umbrella.

The species was diagnosed from its congeners chiefly on the basis of a distinct longitudinal dark stripe running from the supracleithrum (the shoulder region) back to the caudal peduncle, together with a truncate laterosensory system along the head and body. As with many recently described curimatids, C. boiadeiro is known mainly from the type series and follow-up occurrence records rather than from a body of ecological literature, so this account keeps close to what the original description and aggregator databases actually report.

Morphology

Cyphocharax boiadeiro is a small fish: FishBase gives a maximum recorded length of 2.5 in standard length, consistent with the modest size typical of the genus. Like other curimatids it has a fusiform, moderately compressed body built for steady shoaling and grazing rather than the deep, blade-bodied profile of a piranha or the disc shape of a silver dollar, and it lacks the interlocking cutting teeth that define its predatory relatives — curimatids feed by sifting substrate and biofilm rather than biting.

The most distinctive external feature noted in the original description is a longitudinal dark stripe running from the shoulder (supracleithrum) to the base of the tail, which along with a truncate arrangement of the laterosensory (lateral-line) system on the head separates C. boiadeiro from closely related Cyphocharax species in the same drainage. Beyond the diagnostic features used to describe it, detailed morphometric and colour-pattern data have not been captured in the sources available for this account.

Habitat

The species is known from the upper rio Araguaia, part of the Araguaia-Tocantins system within the wider Amazon basin drainage of central Brazil. FishBase classifies it as a benthopelagic tropical freshwater fish, meaning it lives and forages both near the bottom and in open water rather than being strictly bound to the substrate, which fits the grazing, detritus- and biofilm-feeding habit typical of Curimatidae.

No specific pH, hardness or temperature data for C. boiadeiro were found in the sources reviewed for this account, and it would be guessing to assign numbers the type description and aggregator records do not provide. What can be said is that the upper Araguaia is a warm, tropical central-Brazilian river system, and other Cyphocharax and curimatid species in similar Amazon-basin drainages are generally associated with soft-to-moderate, mildly acidic-to-neutral lowland river water — but that is a genus-level generalisation, not a documented figure for this species specifically.

Feeding

Cyphocharax boiadeiro has not itself been the subject of a published diet study among the sources reviewed here, but Curimatidae as a family are characteristically detritivorous, toothless grazers that sift organic sediment, biofilm and algae rather than hunting live prey. A closely related congener, Cyphocharax voga, has been studied directly and found to be overwhelmingly detritivorous — around 96% detritus in stomach contents, with only trace amounts of zoobenthos and zooplankton — which is consistent with, though not proof of, a similar detritus-grazing diet in C. boiadeiro.

In the absence of a species-specific study, the safest statement is that C. boiadeiro is very likely an omnivorous detritus-and-biofilm grazer typical of its genus and family, rather than a predatory or specialist feeder. This distinguishes it sharply from the predatory piranhas and the plant-shredding silver dollars that share this atlas's broader characin coverage.

Mating

No courtship or pairing behaviour for Cyphocharax boiadeiro has been documented in the sources available for this account. Curimatids in general are not known for elaborate courtship display, and without species-specific observation it would be fabrication to describe one here. Data sparse.

Breeding

There is no published breeding record for Cyphocharax boiadeiro in the sources reviewed, and the species is not known to have been bred in the aquarium or in aquaculture. Many curimatids, including migratory relatives in the wider Curimatidae/Prochilodontidae group, are open-water egg-scatterers with no parental care, but that pattern has not been confirmed for this specific species and should not be presented as established fact. Given the lack of evidence, the honest position is that breeding biology for C. boiadeiro is simply unrecorded — data sparse rather than assumed.

In the aquarium

Cyphocharax boiadeiro is not established in the aquarium hobby and no keeping data was found among the sources reviewed for this account. As a small (around 2.5 in), non-predatory, likely detritus-grazing curimatid, it would in principle suit a peaceful community setup sized for a small shoaling fish rather than anything approaching the space, filtration or legal considerations demanded by the true piranhas, pacus or wolf fish covered elsewhere in this atlas — but that is an inference from its family and size, not a documented care record, and prospective keepers should treat any husbandry parameters as unconfirmed until better sources exist.

Given how little has been published on this species outside its original taxonomic description, it is best regarded as a scientifically documented but hobby-obscure curimatid rather than an aquarium fish with an established track record.

Conservation

Cyphocharax boiadeiro has not been evaluated by the IUCN Red List (status: Not Evaluated), which is unsurprising for a species described as recently as 2017 and known from a comparatively restricted type locality in the upper rio Araguaia. No population trend, threat assessment or trade data was found in the sources reviewed for this account.

As with many recently described, single-drainage curimatids, the main conservation-relevant fact is simply that a formal assessment has not yet been carried out — the honest position is that its status is unknown rather than secure, and any statement of risk beyond that would be speculation not supported by the available sources.

Sources

  1. FishBase — Cyphocharax boiadeiro Melo, 2017
  2. Melo, B.F. (2017). Original description, Zootaxa 4247(2):114-120
  3. PubMed — Cyphocharax boiadeiro description record
  4. The trophic role of Cyphocharax voga according to foraging area and diet analysis in turbid shallow lakes
  5. GBIF — Cyphocharax boiadeiro occurrence dataset

Last reviewed 2026-07-09.

How to cite

Aquarist Atlas (2026). Cyphocharax boiadeiro. Aquarist Atlas.https://www.aquaristatlas.com/piranhas/cyphocharax-boiadeiro/

Where it has been recorded

6 georeferenced records (GBIF). Each point is a field observation or museum specimen — pan and zoom to explore where this species turns up. The coordinates come straight from GBIF and are often rounded or tied to the nearest town or river landing, so a dot can sit just beside the actual water rather than in it.

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