Taxonomy & naming
Dundocharax bidentatus was described by the Belgian ichthyologist Max Poll in 1967 and remains the only recognised species in the monotypic genus Dundocharax. It sits in the family Distichodontidae, the African group of characins that also contains the much larger and far better-known Distichodus, within the order Characiformes.
Available records treat the genus as monotypic and the placement in Distichodontidae as settled, but very little taxonomic revision work has touched this species since its description — there is no evidence in the available sources of a later generic transfer or synonymy, so "Dundocharax bidentatus" is used here as the current valid combination. Given how sparse the literature is, any claim beyond the original description and the handful of database entries in the sources below should be treated with caution.
Morphology
Dundocharax bidentatus is extremely small even by the standards of miniature characins: FishBase records a maximum length of 0.5 in standard length (roughly 1 in total length), making it one of the smallest members of its family. No detailed published account of its external morphology, colour pattern or fin shape beyond the original description is available in the sources consulted here, so specific claims about body depth, colouration or fin proportions are not made in this article — readers wanting that level of detail should consult Poll's original 1967 description.
The genus name itself hints at a distinguishing feature (see Etymology), but without a verifiable published account of the live or preserved colouration, no attempt is made here to describe it beyond noting the species' diminutive, pelagic body form as reported by FishBase.
Habitat
Dundocharax bidentatus is known only from the Lucoge River, a tributary of the Chicapa River within the Kasai drainage in Angola — part of the wider Congo River basin. FishBase and iNaturalist both describe it as endemic to this limited area, and observation records are very sparse, consistent with its tiny size and the general under-sampling of small-bodied fishes in this part of Angola.
As with most fish restricted to a single small river system, water there is presumably warm, as is typical of Congo-basin headwater and tributary streams, but no specific published temperature or pH readings for the Lucoge River accompanied this species' description in the sources available, so no numeric water-chemistry range is asserted here beyond a general expectation of warm tropical conditions.
Feeding
No published diet study for Dundocharax bidentatus was found in the sources consulted. Given its placement in Distichodontidae — a family whose better-studied members range from algae- and detritus-grazing citharinids to the herbivorous, plant-grazing Distichodus — and its very small, pelagic body form, it most plausibly feeds on small invertebrates, algae, or fine organic material typical of small stream-dwelling characins, but this is an inference from family-level pattern rather than a documented fact about this species specifically, and should be read as such.
Mating
No courtship or spawning behaviour has been documented for Dundocharax bidentatus in the sources available. Nothing is published on how males and females differ externally, whether pairs form, or what environmental cues might trigger spawning in the wild. Given the complete absence of aquarium-trade presence and the very limited field data on this species, this gap in knowledge is expected rather than an oversight to be filled with speculation.
Breeding
There is no documented breeding record for Dundocharax bidentatus, in the wild or in captivity. It is not established in the aquarium hobby, and distichodontid characins generally — Distichodus and the related citharinids — are egg-scatterers that are notoriously difficult to breed even in professional facilities; there is no basis to assume this tiny, single-river endemic behaves differently, but equally no direct evidence to confirm it does. Given the total absence of husbandry data, no breeding mode can be responsibly claimed for this species beyond noting the pattern typical of its family.
In the aquarium
Dundocharax bidentatus is not a fish anyone will encounter in the aquarium trade. It has no history of collection or export as an ornamental species, no husbandry literature, and a natural range restricted to a single small tributary in Angola that is not a source region for the trade. There is nothing in the available sources to responsibly base a stocking, tank-size or diet recommendation on, and inventing care parameters for a fish with no aquarium history would be irresponsible.
The honest takeaway for a hobbyist audience is that this species illustrates just how much of African characin diversity — outside the familiar, larger Distichodus species that are occasionally seen in the trade — remains essentially undocumented and unavailable outside of scientific collections and museum specimens.
Conservation
Dundocharax bidentatus is assessed as Data Deficient. FishBase and related records note that its distribution knowledge is limited essentially to the type locality on the Lucoge River in Angola's Kasai drainage, with no confirmed records establishing a broader range, population size, or trend. That narrow known distribution, combined with general pressures on Congo-basin freshwater habitats such as land-use change and water-quality degradation, would be a reasonable long-term watch item for a single-river endemic, but no species-specific threat assessment has been published to confirm or quantify that risk.
Given the Data Deficient status, this account does not assert a threatened or secure status for the species — more field survey work in the Kasai drainage would be needed before its true conservation position could be stated with confidence.