Taxonomy & naming
Cyphocharax derhami was described by Richard P. Vari and Fang Chang in 2006, with a type locality at Quebrada Negra, Yanayacu, in the Río Marañón drainage of Loreto in the Peruvian Amazon. It belongs to Curimatidae, the toothless characins — a family of small to medium detritivorous characiforms distinct from the predatory piranhas and the large migratory pacus that dominate popular imagination of the group, and placed among the "minor characins" alongside Hemiodus, Prochilodus, Parodon and their relatives.
The genus Cyphocharax contains numerous species distributed across the Amazon, Orinoco and Paraná basins, most of them small, silvery, deep-bodied grazers that are difficult to tell apart without close examination of mouth and dentition characters. Full-text details from the original Vari & Chang description (published in Neotropical Ichthyology) were not accessible for this article; the genus placement and authority are given here as documented, and the Catalog of Fishes governs the valid combination Cyphocharax derhami.
Morphology
Specific size and body-shape data for Cyphocharax derhami were not found in available sources. Congeners in the genus give a useful frame of reference: C. saladensis reaches about 4 in and C. spilurus about 4 in, while the largest species, C. magdalenae, reaches roughly 10.5 in — so the genus spans a considerable range, and it would be a fabrication to assign C. derhami a specific figure without a source. What can be said with confidence from the family and genus is the general body plan: a small to medium, laterally compressed, silvery characin with a toothless (or near-toothless) mouth adapted for sifting fine organic material, typical of Curimatidae detritivores.
Pending more complete data, this section is deliberately conservative. Anyone needing a precise adult size for C. derhami should consult the original Vari & Chang (2006) description directly.
Habitat
The type locality for Cyphocharax derhami is Quebrada Negra at Yanayacu, in the Río Marañón drainage of the Loreto region of northeastern Peru — the Marañón being a major whitewater tributary of the upper Amazon system. As with other Cyphocharax, it is reasonable to expect the species in lowland river channels and associated floodplain habitats typical of the western Amazon basin, though a fuller range map beyond the type locality was not available in the sources consulted here.
Water-chemistry data specific to C. derhami — temperature, pH, hardness — were not documented in the cached sources. The genus as a whole is South American (Amazon, Orinoco and Paraná basins), and Amazonian lowland tributaries in this region are typically warm and circumneutral to mildly acidic, but assigning precise figures to this species without a direct source would be guessing, so none are given.
Feeding
Cyphocharax derhami is, by genus, a detritus feeder — the GBIF record for the species explicitly notes this trait, consistent with the family Curimatidae's toothless, sediment-sifting feeding mode. Like its relatives, it likely grazes fine organic detritus, biofilm and associated microfauna from substrate and submerged surfaces rather than pursuing live prey or browsing plant material directly.
No aquarium-specific feeding notes exist for this species, since it does not appear to be established in the hobby. In a general Curimatidae-type diet, a captive analogue would be sinking algae- or spirulina-based wafers and fine detrital foods rather than a meat-heavy diet, but this is an inference from the genus rather than a documented fact about C. derhami.
Mating
No courtship or spawning behaviour has been documented for Cyphocharax derhami in the sources available. The species does not appear in the aquarium trade or aquaculture literature, so there is no hobbyist or commercial breeding record to draw on, and nothing should be inferred about pairing behaviour or sexual dimorphism beyond noting that none is documented.
Breeding
Breeding mode for Cyphocharax derhami is not documented in the cache or in general literature accessible for this article. It would be inaccurate to assign it a specific reproductive strategy without evidence; many minor characins in this group are egg-scatterers with no parental care, but that is a genus-level generalisation, not a confirmed fact for this species, and it is not stated as one here.
There is no record of this species being bred in captivity, commercially or otherwise. This is unsurprising given it has no established presence in the aquarium trade.
In the aquarium
Cyphocharax derhami is not a hobby fish. No aquarium care literature, retailer listings or hobbyist accounts of this species were found, and it should not be assumed to be available in the trade. Prospective keepers interested in the genus's general character — small, schooling, detritus-grazing characins — are better served by the handful of Cyphocharax species that do appear occasionally in specialist imports, where care parameters are actually documented.
Given the complete absence of husbandry data, no tank size, water parameter or tankmate recommendations are offered here; doing so would mean inventing information this species' record does not support.
Conservation
The IUCN Red List assesses Cyphocharax derhami as Least Concern, consistent with GBIF's occurrence data for the species. As a narrow-range Amazonian tributary fish with no evidence of significant trade pressure or documented habitat threats in the sources reviewed, its Least Concern status reflects an apparent lack of known population decline rather than an actively monitored abundance trend.
No specific conservation concerns, threats or watch-list flags are recorded for this species beyond the general, basin-wide pressures — deforestation, sedimentation and hydrological change — that affect Amazonian freshwater fish broadly.