Taxonomy & naming
Enteromius stauchi was described by the French ichthyologist Jacques Daget in 1967, with the original combination Barbus stauchi. It was subsequently transferred to Enteromius, the large genus of African small barbs whose limits have shifted considerably as the old catch-all genus Barbus has been progressively subdivided. The Catalog of Fishes (Eschmeyer, CAS) records the valid combination as Enteromius stauchi (Daget, 1967), with the parenthetical authority acknowledging the genus transfer.
FishBase notes that E. stauchi may be a synonym of Enteromius rubrostigma, a suggestion that has not been formally resolved. Until a revisionary study either synonymises the name or confirms its distinctness, E. stauchi is maintained as a valid species. The species epithet stauchi honours a collector or contributor named Stauch, following a common tradition in Daget's West and Central African descriptions.
Morphology
Enteromius stauchi is a small barb, reaching a maximum recorded size of 3.5 in standard length (male or unsexed) according to FishBase. Like most members of the genus it has the moderately deep, laterally compressed body typical of stream-dwelling Enteromius, with a slightly arched dorsal profile and a subterminal mouth suited to picking invertebrates and organic material from the substrate and water column.
Detailed meristic and colour descriptions from the original Daget description are sparse in the available literature. As a benthopelagic species of Lower Guinea's coastal drainages, it likely shares the cryptic silvery-to-olive flanks and reduced patterning common in small riverine Enteromius from this biogeographic zone, but specific pattern data remain scarce.
Habitat
Enteromius stauchi is endemic to the coastal river systems of Lower Guinea — specifically the Loémé River and the Niari-Kouilou basin in the Republic of Congo. These are relatively small, low-gradient coastal drainages that descend from the Mayombe massif and associated uplands to the Atlantic coast, flowing through a mix of forest and savanna-margin landscapes.
Water chemistry data specific to E. stauchi from these basins have not been captured in the available literature. The Loémé and Niari-Kouilou rivers likely experience seasonal variation in flow and turbidity, with softer water in forested headwater reaches and progressively harder conditions downstream. The species is described as benthopelagic, suggesting it occupies the bottom and mid-water column of streams and rivers rather than specialising in surface habitats.
Feeding
Specific dietary data for Enteromius stauchi are not available in the accessible literature. As a typical small Enteromius of West-Central African rivers, it is presumed to be an opportunistic omnivore, taking small invertebrates — insect larvae, crustaceans, and worms — as well as algal biofilm, detritus, and plant material picked from the substrate and water column, consistent with the guild ecology of benthopelagic barbs in the region.
In aquarium settings, small barbs of this type generally accept quality flake and micro-pellet foods readily, along with live and frozen invertebrate foods such as bloodworm and brine shrimp nauplii.
Mating
Like all barbs, Enteromius stauchi is an egg-scattering, non-guarding spawner. Courtship involves a driving male pursuing a gravid female through vegetation or over the substrate, and eggs and milt are released together in brief contact. No pair bond, nest, territory, or parental care follows spawning — the eggs are left to their own fate among plants, roots, and substrate debris.
Specific field observations of mating behaviour in E. stauchi are not documented in the available literature, but the reproductive strategy is consistent across the genus and the broader cyprinid tribe to which Enteromius belongs.
Breeding
No captive breeding records for Enteromius stauchi are known from the hobby literature, reflecting its obscurity in the aquarium trade. The reproductive biology is inferred to follow the pattern universal in the genus: adhesive or semi-adhesive eggs scattered over fine-leaved plants, root tangles, or gravel, with no parental care and adults that will consume eggs given the opportunity.
In general, small Enteromius bred in captivity are managed like other egg-scattering barbs — soft, slightly acidic water, a separate spawning vessel, and prompt removal of adults after spawning to protect the clutch.
In the aquarium
Enteromius stauchi is essentially unknown in the ornamental fish trade. Its restricted range in the Republic of Congo and its Endangered status mean that wild-caught individuals rarely if ever reach the hobby, and no captive breeding programme appears to exist. Information on aquarium husbandry is therefore largely inferential.
As a small riverine Enteromius from a tropical West-Central African drainage, it would be expected to do best in a well-oxygenated, moderately planted aquarium with warm water, a neutral-to-slightly acid pH, and low to moderate hardness reflecting its Lower Guinea coastal river origins. A small shoal of six or more would be appropriate for a species accustomed to group living in stream environments.
Conservation
Enteromius stauchi is assessed as Endangered on the IUCN Red List (2020 assessment). The Endangered listing reflects the species' extremely limited endemic range — confined to the Loémé and Niari-Kouilou basins in the Republic of Congo — combined with ongoing habitat degradation across Lower Guinea's coastal river systems.
Throughout this zone, freshwater habitats face mounting pressure from agricultural conversion (particularly oil palm and cassava cultivation), artisanal and industrial logging in the Mayombe forest, artisanal mining, and the associated siltation and water-quality deterioration of streams and small rivers. The Niari-Kouilou basin is among the more developed drainages in the Republic of Congo, increasing the exposure of its endemic fauna to catchment-scale modification. With no recorded presence in the aquarium trade and no ex-situ safety net, E. stauchi's long-term security depends entirely on the persistence of intact habitat within its tiny native range.