Taxonomy & naming
Enteromius vandewallei was formally described in 2016 by J.-M. Lederoun and E. Vreven in a paper treating a new species of minnow from the Volta River basin of West Africa (Cypriniformes, Cyprinidae). The species was not transferred from an older Barbus or Puntius combination — it was described directly into Enteromius, a genus that has long served as the principal container for small African barbs and barbels.
The Catalog of Fishes (Eschmeyer, CAS) records the valid name as Enteromius vandewallei Lederoun & Vreven, 2016. The species is placed in the West African group of Enteromius characterised by a weakly ossified, flexible, and smooth-edged final dorsal-fin ray — a feature that separates this clade from the strongly ossified dorsal-ray groups found elsewhere in the genus. Within that group, E. vandewallei is most similar to E. nigeriensis, and specimens had been misidentified as that species prior to the formal description. The species epithet honours an individual associated with the study, though the original publication's full etymology is not reproduced in available secondary sources.
Morphology
Enteromius vandewallei is a small, slender barb with a maximum recorded length of 2 in standard length (SL) based on FishBase data for male or unsexed individuals. Like other members of the West African Enteromius clade, it carries two pairs of barbels — one rostral and one maxillary — which are characteristic of the genus and help distinguish it from the one-barbel-pair groups.
A prominent dark longitudinal band running along the flanks is a key diagnostic feature and the character most likely to cause confusion with Enteromius nigeriensis in the field. The precise meristic and morphometric details separating E. vandewallei from E. nigeriensis are set out in the original 2016 description. Beyond these defining traits, available secondary sources are sparse on colour pattern details, and the full meristic data are best consulted in Lederoun and Vreven's primary paper.
Habitat
Enteromius vandewallei is recorded from the Volta River basin, a large drainage system that spans Benin, Burkina Faso, and Ghana in West Africa. The Volta basin includes a wide range of freshwater habitats from savanna-zone rivers and seasonal streams to larger perennial tributaries, and small Enteromius in this region typically occupy the benthopelagic zone of shallow to medium-depth freshwater environments.
FishBase classifies the species as a tropical freshwater fish. Water chemistry in Volta basin tributaries varies with geology and season; savanna and sub-Sahelian portions of the drainage tend toward harder, more neutral to slightly alkaline conditions compared with the softer, more acidic waters of forest-zone headwaters further south. Specific temperature, pH, or conductivity records for E. vandewallei are not captured in available sources, but conditions across the Volta drainage for small barbs are broadly tropical, with warm year-round temperatures.
Feeding
Detailed dietary data for Enteromius vandewallei are not available in published secondary sources. Based on its size, body form, and membership in the West African Enteromius clade, it is expected to be a generalist omnivore in the manner typical of small African barbs — foraging along the bottom and in the water column for small invertebrates, algae, detritus, and plant material.
Small Enteromius of the Volta basin share their habitat with other minnow-sized fishes and are likely opportunistic feeders responding to seasonal fluctuations in food availability that accompany the pronounced wet and dry seasons of the West African savanna zone.
Mating
No species-specific mating observations have been published for Enteromius vandewallei. As a member of the barb family (Cyprinidae), it is an egg-scattering, non-guarding spawner — the reproductive mode universal across barbs. There is no nest, no pair bond sustained beyond the spawning act, and no parental care of any kind.
In the wild, small West African Enteromius are likely seasonal spawners tied to the onset of rains and the rise in river levels, when warmer, well-oxygenated flood waters trigger reproductive activity. Courtship involves a driving male pursuing a gravid female through vegetation or over the substrate, the two briefly pressing together to release eggs and milt simultaneously.
Breeding
Enteromius vandewallei has not been bred in captivity in any documented aquarium context. Its reproductive biology follows the barb pattern: eggs are adhesive and scattered among fine-leaved plants, roots, or over the substrate with no parental care — adults may consume the eggs if not separated. The number of eggs per spawn, incubation time, and larval development have not been reported for this species.
In the absence of captive-breeding records, the general approach used for similar small West African barbs would apply: soft to moderately hard water at tropical temperatures, fine-leaved plants or a spawning mop as an egg-catching medium, and removal of adults after spawning to protect the eggs.
In the aquarium
Enteromius vandewallei is not an established aquarium fish, and it is not known to be available in the ornamental trade. It is a very small species — under 2 in SL — from savanna-zone West African rivers, and it has been described only recently (2016), so captive-husbandry information is essentially absent from hobbyist literature.
If the species were to become available, its small size and likely peaceful temperament would suit a species tank or a quiet community with similarly sized West African fishes. Water conditions reflecting the Volta basin — tropical temperatures, moderate hardness — would be appropriate starting points. Given the Data Deficient IUCN status and the limited knowledge of its wild populations, this species would be of greater value in a research or conservation aquaculture context than as a routine trade fish.
Conservation
Enteromius vandewallei is assessed as Data Deficient (DD) on the IUCN Red List, assessed on 7 May 2019. The Data Deficient rating reflects insufficient information to make a reliable determination of extinction risk — not necessarily that the species is rare, but that its population size, range extent, and trends have not been adequately quantified since its description in 2016.
The Volta River basin faces growing pressures from agricultural expansion, damming (the Akosombo and Kpong dams on the lower Volta have restructured the basin's hydrology), sedimentation from land clearance, and seasonal water extraction in the drier northern portions of the drainage. Small, potentially range-restricted Enteromius species are particularly vulnerable to localised habitat degradation. Targeted surveys of E. vandewallei's distribution and abundance in Benin, Burkina Faso, and Ghana would be needed to support a meaningful IUCN reassessment.