Taxonomy & naming
Cyphocharax cramptoni was described by Bortolo and Lima in 2020 in Neotropical Ichthyology, as part of a paper on new species of Cyphocharax from northern Brazil. It belongs to the family Curimatidae — the toothless "curimatas," a large group of small to medium detritivorous characins within the order Characiformes — and to the genus Cyphocharax, which the Catalog of Fishes and WoRMS both list as a valid, currently accepted genus within that family.
The genus Cyphocharax comprises many similar-looking small silver characins distinguished mainly by fine differences in scale-row pigmentation, body proportions and osteology rather than by anything visible at a glance, which is typical of curimatids generally. No information from the cited sources documents the origin of the specific epithet "cramptoni"; given the pattern of many recent curimatid descriptions, it plausibly honours a collector or supporter of the fieldwork, but that is not confirmed by the available sources and is not stated here as fact.
Morphology
The original description reports a holotype of 2 in standard length (SL), with type-series specimens ranging from 1–2 in SL — in round terms, an adult of well under 2 in. Like other members of its genus, Cyphocharax cramptoni is toothless, part of the curimatid strategy of grazing organic material and biofilm rather than biting prey or plant matter.
The species is characterised by a horizontal colour pattern of dark stripes and spots running between the scale rows along the flank, a common diagnostic tool used to separate Cyphocharax species from one another. Beyond size and this pigmentation pattern, the source material does not describe fin counts, body depth or other detailed morphometrics, so this account keeps to what the description documents rather than extrapolating from congeners.
Habitat
Cyphocharax cramptoni is known only from its type locality: the Rio Mentaí, a tributary of the Rio Arapiuns in the lower Rio Tapajós drainage, Pará state, Brazil (recorded at approximately 2°43'28.64"S, 55°36'5.60"W). At the collection site the river was described as a small clearwater channel roughly 33–49 ft wide, with a sandy bottom and submerged vegetation — a modest tributary rather than a major river channel.
Water conditions recorded at the type locality were warm and notably soft and acidic: 80 °F, pH 4.2, conductivity 11.8 µS/cm and dissolved oxygen 5.5 mg/l — figures consistent with a nutrient-poor, blackwater-influenced clearwater tributary. As a newly described species known from a single site, its true range may extend further through the Tapajós system pending additional survey work, but that has not been confirmed in the cited sources.
Feeding
The original species description does not document gut contents or diet directly for Cyphocharax cramptoni. However, the genus as a whole is characterised on FishBase as toothless, small, omnivorous-to-detritivorous characins typical of the Amazon basin and its tributaries, grazing organic detritus, biofilm and fine algae from sediment and submerged surfaces rather than pursuing prey or browsing on coarse plant material.
Given the clearwater, sandy-bottomed, vegetated habitat recorded at the type locality, a detritus- and biofilm-grazing lifestyle typical of its relatives is the reasonable inference, but no direct dietary data for this species has been documented in the available sources, and none is asserted here beyond that inference.
Mating
No courtship, pairing or sexual dimorphism has been documented for Cyphocharax cramptoni in the cited sources. The original description is a taxonomic account built from preserved type specimens rather than a field or aquarium study of behaviour, and none of the other cached sources add behavioural detail. This is genuinely unknown territory rather than an oversight to fill in with assumptions from other curimatids.
Breeding
There is no documented breeding record for Cyphocharax cramptoni, in the aquarium or in the wild. As with the rest of its family, curimatids are presumed to be open-water or scatter-type egg-layers based on general characin biology, but that mode has not been confirmed for this specific species in any source consulted, and the species is not known to have ever been bred or even maintained in captivity.
Given that it is known from a single small Amazonian tributary and was described only in 2020, it should be treated as essentially unstudied outside its original taxonomic description — data sparse, not zero.
In the aquarium
Cyphocharax cramptoni has no known presence in the aquarium hobby. It is not a trade species, has not been reported as an import, and nothing in the available sources describes tank requirements, temperament or compatibility from a keeper's perspective. Any care guidance here would be extrapolation from its Curimatidae relatives rather than fact about this species, so none is offered.
What can be said honestly is only what the type-locality data implies: a small (under 2 in), soft-water, warm-water fish from an acidic, low-conductivity clearwater river, which — if it were ever collected for the trade — would point toward a peaceful, small-shoaling grazer rather than anything resembling the piranhas or pacus that give this family group its popular name.
Conservation
Cyphocharax cramptoni's IUCN status was reported as Least Concern (LC) in the cached source review, though no formal IUCN Red List assessment page for this specific species was located among the cited sources — the status should be treated with appropriate caution pending a direct citation. The species is known only from its type locality in the Rio Mentaí, a tributary of the Rio Arapiuns in the lower Rio Tapajós basin, and has not been reported as more widespread.
As a narrow-range, recently described species with a single documented locality, its long-term conservation picture depends on the health of that specific tributary and the wider Tapajós drainage, which faces the general Amazonian pressures of deforestation, agricultural runoff and water-quality change, though no species-specific threat assessment has been documented in the available sources.