Taxonomy & naming
Cyphocharax laticlavius was described by Richard P. Vari and Christine Blackledge in 1996. It belongs to the family Curimatidae — the toothless, detritus- and algae-grazing curimatas — within the order Characiformes, the same broad characin lineage that includes the piranhas, pacus and silver dollars of Serrasalmidae, though Cyphocharax and its curimatid relatives are a distinct, much quieter branch with no dentition specialised for cutting flesh or plant material.
The genus Cyphocharax comprises a large number of small South American species that are frequently difficult to distinguish without close examination of meristic counts and body markings; the Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the standing authority for the valid combination Cyphocharax laticlavius. The species is known with confidence only from its type locality — a tributary of Jatuncocha Lagoon in the Napo drainage of Ecuador — and has not accumulated the synonymy history of more widespread congeners.
Morphology
Cyphocharax laticlavius is a small, slender-bodied curimatid, with FishBase recording a maximum length of 2 in standard length — modest even by the standards of a genus made up largely of small fish. Meristic counts given for the species are 11–12 dorsal soft rays, 9 anal soft rays and 30–32 vertebrae, figures consistent with the generally streamlined, laterally compact body typical of curimatids built for steady grazing rather than bursts of predatory speed.
The species' most distinctive external feature is a dark midlateral stripe that runs from the hypural joint (the base of the tail) forward to the base of the dorsal fin — a marking used, alongside the meristic counts, to separate it from superficially similar Cyphocharax species in the same drainage. Beyond this stripe and its diminutive size, detailed colour and finnage description is sparse in the available literature.
Habitat
The species is documented only from shallow, slow-moving blackwater streams with sandy bottoms in tributaries of Jatuncocha Lagoon, part of the upper Napo River system in Ecuador. This is a tropical freshwater, benthopelagic habitat — the fish forages near the bottom and in the lower water column rather than at the surface — within a comparatively small and specific catchment rather than across a broad river basin.
Detailed water chemistry for the type locality is not recorded in the cached sources; blackwater habitats of this kind in the upper Amazon are typically warm and on the soft, acidic side, but specific pH and hardness figures for this stream are not documented here and should not be assumed. The species' apparent confinement to this small tributary system, rather than the wider Napo or Amazon basin, is central to its conservation status (see "Conservation").
Feeding
As a member of Curimatidae, Cyphocharax laticlavius almost certainly follows the family's well-documented pattern of grazing on detritus, biofilm, algae and fine organic material sifted from sand and sediment, using a toothless, downturned mouth adapted for that purpose rather than for capturing prey. This places it firmly in the quiet, detritivorous end of the characin spectrum — nothing like the predatory reputation of piranhas or the plant-shredding habits of silver dollars.
No species-specific feeding study or aquarium diet record is available in the cached sources, so this account follows the documented biology of the genus and family rather than direct observation of C. laticlavius itself; data on this species' feeding is sparse.
Mating
No courtship or spawning-behaviour data for Cyphocharax laticlavius appears in the cached sources. Curimatids as a group are generally understood to be open-water or substrate egg-scatterers with no pair-bonding or nest-building, but that pattern has not been specifically confirmed for this species, and no external sexual dimorphism is documented for it either. Data sparse.
Breeding
There is no documented breeding record for Cyphocharax laticlavius, in the wild or in captivity — unsurprising for a small, narrow-range species that is not established in the aquarium trade. It should not be assumed to follow any particular breeding mode (egg-scattering, nest-building or otherwise) without direct evidence; the honest position is that its reproductive biology is effectively unstudied. Aquaculture or hobby breeding programs for this species do not appear to exist.
In the aquarium
Cyphocharax laticlavius is not established in the aquarium hobby: the cached research turned up no aquarium care information, and the species does not appear to be commonly, or perhaps ever, imported for the trade. Its small adult size (around 2 in SL) would in principle suit a modest aquarium, and its grazing, detritivorous habits suggest it would be an unobtrusive, peaceful bottom-and-midwater forager rather than a fish that needs the large-tank, group-defence or predator-management considerations that dominate care of its piranha and pacu relatives.
Given the complete absence of husbandry data, any tank parameters offered here would be speculation rather than documented care advice. Prospective keepers should treat this as a species without an established aquarium record rather than infer conditions from more commonly kept Cyphocharax or curimatid relatives.
Conservation
The IUCN Red List assesses Cyphocharax laticlavius as Vulnerable (VU), an assessment dated 29 March 2021 made under criterion D2 — reflecting a very restricted range confined to a small number of locations, in this case tributaries of the upper Napo drainage in Ecuador, where a single damaging event (such as habitat degradation or pollution) could rapidly threaten the entire known population. The U.S. Fish & Wildlife Service's species listing corroborates the Vulnerable status and confirms the species' distribution as restricted to Ecuador.
Because the species is not part of the aquarium trade, collection pressure is not a documented threat; the relevant risks are the general pressures facing small-range Amazonian headwater streams, including deforestation, water-quality change and habitat disturbance within its narrow known range, though the cached sources do not detail a specific threat assessment beyond the range-restriction criterion itself.