Taxonomy & naming
The species was described by the French ichthyologist Jacques Pellegrin in 1921 as Barbus rohani. Pellegrin's original placement in Barbus was routine for the era; the genus served as a catch-all for Old World small barbs through most of the twentieth century. The species was subsequently transferred to Enteromius, the large genus used for African barbs derived from the old Barbus complex, and that combination is retained in GBIF (accession 5206725) and some databases.
A significant taxonomic revision by Pethiyagoda and colleagues published in 2012 split the South Asian barb complex, erecting several new genera for Indian and Sri Lankan species. Under that revision the species is recognised as Dawkinsia rohani, placed in a genus named for the ichthyologist Rohan Pethiyagoda. The epithet rohani itself honours Pethiyagoda in the original description. Seriously Fish and aquarium references now use the combination Dawkinsia rohani. The Catalog of Fishes is the authority for valid names and should be consulted for the current accepted combination.
The placement of this species in Enteromius creates a geographic anomaly: Enteromius is principally an African genus, whereas rohani is endemic to the Western Ghats of peninsular India. Whatever the final nomenclatural resolution, the species belongs biologically to the South Asian hill-stream barb fauna, not to the African radiation.
Morphology
Enteromius rohani is a small, moderately deep-bodied barb. Published aquarium sources describe the colouration in some detail: the upper body carries a distinctive yellow-green lattice or fishnet-patterned reticulation, while the flanks below are silvery. A prominent dark teardrop or comma-shaped mark sits above the caudal peduncle. The dorsal fin is red with a black margin; the caudal and anal fins are reddish. The overall impression in life is of a boldly marked species with warm tones contrasting against the silver-and-dark patterning of the body.
Precise size data for this species are not captured in available sources. As a Western Ghats hill-stream barb of the Dawkinsia lineage it likely falls in the small-to-moderate range typical of the group — broadly in the 2–4 in range — but a confirmed maximum length cannot be stated from the available cache.
Habitat
The species is recorded from the hill streams of Tamil Nadu in southern India, specifically from the Kanyakumari District, in streams that drain the southern Western Ghats toward the Arabian Sea. Sources describe it as inhabiting cool, fast-moving freshwater streams — a typical Western Ghats hillstream habitat characterised by well-oxygenated, clear water running over rocky or gravelly substrate.
The Western Ghats represent one of the world's biodiversity hotspots, and their freshwater systems are noted for high levels of endemism. Hill streams in this region typically have soft to moderately mineralised water, rocky beds, and strong seasonal variation in flow driven by the southwest monsoon. Specific water chemistry figures (temperature, pH) for E. rohani at its collection localities are not available in the researched sources.
Feeding
No detailed dietary studies of Enteromius rohani in the wild are available from the researched sources. By analogy with other small Western Ghats hill-stream barbs, the species is likely an opportunistic omnivore, taking small invertebrates, algae, and organic material from the stream substrate and water column.
In aquarium conditions published accounts indicate it accepts standard prepared foods supplemented with live and frozen invertebrate items. Its bold colouration and active disposition make it an attractive aquarium subject, and hobbyist sources treat it as an undemanding feeder under captive conditions.
Mating
Like all barbs, Enteromius rohani is an egg-scattering, non-guarding spawner. No nest is built and no parental care is provided. Spawning behaviour follows the pattern shared across the family: a driving male pursues a gravid female through vegetation or over the substrate, and eggs and milt are released together. The adhesive eggs sink among plants, gravel or other substrate where the parents take no further interest in them.
Specific courtship observations for this species in the wild or in captivity are not reported in the researched sources. Colour intensity in males likely peaks during courtship as in related species.
Breeding
Enteromius rohani is an egg-scattering barb with no parental care. Specific captive-breeding accounts for this species are not available in the researched sources; the species remains uncommon in the hobby. By analogy with related Western Ghats barbs, breeding would be induced by clean, well-oxygenated water, conditioning on live foods, and a slight temperature drop or increase in water flow simulating the monsoon-season cues that trigger spawning in hill-stream species.
Eggs would be scattered over fine-leaved plants or rocky substrate, with adults removed promptly thereafter to prevent egg predation. Larvae would require fine live foods (infusoria, newly hatched brine shrimp) in the early days after becoming free-swimming.
In the aquarium
Enteromius rohani has appeared in the ornamental trade under its Dawkinsia combination, described by hobbyist sources as an attractive and active species suited to an aquarium replicating its hill-stream origins: good water movement, high oxygenation, clear water, and a rocky or gravel substrate. The vivid dorsal and caudal colouration make it a visually striking subject.
As a shoaling barb it should be kept in groups of at least six. Water conditions appropriate to its Western Ghats hill-stream habitat — cool to subtropical temperatures, moderate hardness, neutral to slightly acidic pH — are recommended, though specific parameters cannot be given with confidence from available data. Long-finned and slow-moving tankmates are best avoided given the active, nippy disposition common to small barbs.
Conservation
No formal IUCN Red List assessment has been located for Enteromius rohani or Dawkinsia rohani. The species' status must therefore be treated as Not Evaluated (NE) at this time, though its restricted endemic range in the southern Western Ghats places it among a freshwater fauna under significant and well-documented pressure.
The Western Ghats freshwater ichthyofauna faces multiple concurrent threats: deforestation and plantation agriculture degrading stream catchments, water extraction for irrigation and domestic use, damming of rivers, sand mining, and pollution from agricultural runoff. Many endemic hill-stream fishes of Tamil Nadu and Kerala have restricted ranges of a few river systems or even a single watershed, leaving them with little buffer against local habitat loss. Collection for the ornamental trade, while of uncertain scale for this species, adds a further pressure. The absence of an IUCN assessment means the species lacks formal international conservation recognition, which itself hampers targeted protection efforts.