Taxonomy & naming
Xenocharax spilurus was described by the English ichthyologist Albert Günther in 1867. It sits in the genus Xenocharax within the family Distichodontidae, part of the African-endemic branch of the order Characiformes that also includes the citharinids (Citharinidae) and the pike-characin Hepsetus. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the standing authority for the valid combination Xenocharax spilurus, and nothing in the available record suggests a synonymy or genus reassignment worth flagging here.
Distichodontidae as a family is defined mainly by dentition and jaw structure rather than by a single body plan, which is why its genera range from small grazers to the metre-plus Distichodus lusosso. Xenocharax spilurus is one of a small number of described Xenocharax species, and — like much of the Congo basin's characin diversity — it is far better represented in taxonomic and distributional literature than in any account of its living behaviour.
Morphology
Published length records for Xenocharax spilurus run from about 6–8 in, a modest adult size for a distichodontid and well short of the large, plant-shredding Distichodus species it is sometimes grouped with in casual accounts. Detailed morphological data exists mainly in the form of CT-scan and skeletal imaging from museum specimens rather than a field-guide-style description of live colouration or fin shape, so this account does not assert details — body depth, mouth position, fin colour — that are not documented in the sources available.
What is documented is its phylogenetic placement: specimen-based work treats Xenocharax as part of a relatively basal clade within Characiformes, underlining how old and distinct the African branch of the order is from its far more diverse South American relatives.
Habitat
Xenocharax spilurus is known from the Lower Guinean ichthyofaunal province and the Congo River basin, with confirmed records spanning Cameroon, Gabon, the Republic of Congo and the Democratic Republic of the Congo. The type locality is a bridge crossing on the Ogooué River in Haut-Ogooué Province, Gabon; other documented material includes a specimen taken from the Lékoli River inside Odzala National Park, Republic of Congo — a well-forested, blackwater-influenced tributary system typical of the wider Congo basin.
No detailed water-chemistry study specific to this species is available in the sources reviewed, so this account does not invent temperature or pH figures. In general terms consistent with its range, Congo-basin rivers of this kind run warm year-round and are frequently soft and tannin-stained where they drain rainforest catchments, but a keeper or reader should treat any numeric water parameters for this exact species as unconfirmed rather than sourced.
Feeding
No species-specific diet study for Xenocharax spilurus was found in the available sources — attempts to research its feeding turned up confounding results for the unrelated South American sailfin tetra Crenuchus spilurus, which shares the species epithet but nothing else. Rather than borrow a diet profile from a different fish because the names look alike, this account states plainly that Xenocharax spilurus's feeding ecology is not documented in the sources reviewed.
Broadly, Distichodontidae as a family leans toward plant material, algae, detritus and small invertebrates rather than active predation, and a cautious reader can treat that family-level pattern as a reasonable working assumption for Xenocharax — but it should not be read as a confirmed fact about this particular species.
Mating
No courtship or pairing behaviour has been documented for Xenocharax spilurus in the sources available. There is no record of external sexual dimorphism, spawning coloration, or pair-formation behaviour for this species, and this account does not speculate on any of it.
Breeding
Xenocharax spilurus has no documented breeding record, in the wild or in captivity. Consistent with the wider pattern in Distichodontidae — where genera such as Distichodus and the citharinids are egg-scattering broadcast spawners that are rarely, if ever, bred in home aquaria — there is no reason to expect this species is any different, but no confirmed account of its spawning mode, egg type or parental care exists in the sources reviewed. This account does not assign it a breeding mode beyond that honest gap.
In the aquarium
Xenocharax spilurus does not appear to be an established aquarium fish. No hobby care guide, retailer listing or aquarist forum account turned up in the research for this species, and its adult size of roughly 6–8 in would in any case call for a larger, well-filtered setup typical of an active, open-water African characin rather than a nano tank. Anyone encountering this species for sale or in a shipment should treat it as effectively undocumented in captivity and research further before committing to it, rather than relying on generic Distichodontidae care advice.
Given the total absence of trade or husbandry information, this account makes no specific recommendations on tankmates, diet in captivity, or breeding setup — doing so would mean inventing detail the sources do not support.
Conservation
Xenocharax spilurus has not been assessed by the IUCN Red List; its status is Not Evaluated. This is common for narrow-range or poorly studied Congo-basin characins that fall outside commercial fisheries and the aquarium trade, and it reflects a lack of assessment rather than any evidence the species is secure or declining.
Its confirmed range across Cameroon, Gabon, the Republic of Congo and the DRC includes both well-protected forest reserves — one record comes from within Odzala National Park — and areas facing the broader pressures common to Congo-basin rivers, including deforestation-linked sedimentation and, in places, artisanal fishing pressure. Without a formal assessment, this account does not characterise the species' population trend or extinction risk beyond noting that data is sparse.