Taxonomy & naming
Neolissochilus acutirostris was formally described by Arunachalam, Sivakumar and Murugan in 2017 in the journal FishTaxa, as one of five new Neolissochilus species from streams and rivers of the Western Ghats of peninsular India. The description was grounded in meristic and morphometric characters combined with molecular data, following a methodological approach that revealed considerable cryptic diversity within what had previously been treated as a single or few broadly distributed taxa. The holotype, ZSI/SRS F 7152, measures 9 in standard length and was collected from a stream at Abby Falls in the Cauvery River drainage, Kodagu District, Karnataka.
The genus Neolissochilus was erected by Rainboth in 1985 for a group of large, robust cyprinids distributed across South and Southeast Asia. These fishes are closely allied to the mahseers (Tor) and share their preference for swift, oxygen-rich hill-stream environments. The Catalog of Fishes recognises the valid combination as Neolissochilus acutirostris Arunachalam, Sivakumar & Murugan, 2017. As a species described only in 2017, it does not carry a prior combination in Puntius or Barbus. The specific epithet acutirostris — from the Latin acutus (sharp, pointed) and rostrum (snout, beak) — refers to a characteristic feature of the fish's head profile that distinguishes it from congeners.
Morphology
Neolissochilus acutirostris is a large barb; the holotype reaches 9 in standard length, indicating adults attain at least 10 in SL, placing this species among the bigger members of its genus. As the epithet suggests, the species is distinguished by a notably pointed snout, a character used in the original morphometric analysis to separate it from closely related Western Ghats congeners. Like other members of Neolissochilus, the body form is expected to be robust and fusiform — adapted to holding station in fast-running water — with a moderately large head, strong musculature across the caudal peduncle, and scales of moderate to large size.
Full meristic and morphometric data are published in Arunachalam et al. (2017); beyond the pointed snout and the standard-length measurements of the type series, detailed external colour pattern descriptions are not available from the cached sources. Given the family-level biology of Neolissochilus, the species almost certainly shows subdued sexual dimorphism, with gravid females becoming noticeably deeper-bodied during the breeding season.
Habitat
The type locality of Neolissochilus acutirostris is a stream associated with Abby Falls in the Cauvery River drainage, Kodagu District, Karnataka — a hill-stream environment in the interior Western Ghats. The Cauvery (Kaveri) is one of the great rivers of peninsular India, rising in the Brahmagiri Hills and draining southward through Karnataka and Tamil Nadu. Its headwater tributaries in Kodagu are characteristically clear, cool, fast-flowing watercourses over cobble and rock substrates, with high dissolved oxygen concentrations sustained by the tumbling gradient.
Studies of congeners such as Neolissochilus stracheyi (the blue mahseer) confirm that the genus as a whole prefers clear, fast-flowing hill streams with cool temperatures, high oxygen availability, and low turbidity — characteristic conditions of forested Western Ghats and Himalayan foothills catchments. Neolissochilus acutirostris, as a Western Ghats endemic confined to the Cauvery drainage, almost certainly occupies the same ecological niche: rocky-bottom hill-stream runs and riffles at mid to upper elevations within the ghats.
Feeding
No published dietary study specific to Neolissochilus acutirostris is available. The genus Neolissochilus, like other large Asian barbs and mahseers, is generally regarded as an opportunistic omnivore of the hill-stream benthos, consuming algae, periphyton, aquatic invertebrates including insect larvae and crustaceans, and organic detritus sourced from the substrate and leaf litter. Large members of the group occasionally take small fish and fallen fruit where these are available seasonally.
The pointed snout that gives the species its name may reflect an adaptation for rooting or probing among rock crevices and gravel for invertebrate prey, though this interpretation is speculative without direct gut-content data. The fast-water, cobble-substrate habitat of the Cauvery headwaters supports a productive benthic invertebrate community on which a large barb of this type would primarily feed.
Mating
Neolissochilus acutirostris is an egg-scattering, non-guarding spawner in the manner universal among barbs. No specific observations of courtship behaviour for this species have been published, but the biology of the genus and family is consistent: during the breeding season, which in hill-stream barbs of monsoon-driven river systems is typically tied to the onset of seasonal rains and rising water levels, males pursue and drive gravid females through the current or over suitable gravel and rock substrates.
Spawning is a brief, vigorous event in which eggs and milt are released together into the current or onto the substrate. No pair bond persists beyond the act of spawning, no territory is defended after release, and adults do not recognise or protect their own eggs. Large river barbs including mahseer-allied species are broadcast spawners that may undertake limited upstream migrations to spawning grounds at the appropriate season, but the details of such movements in Neolissochilus acutirostris remain undescribed.
Breeding
Like all barbs, Neolissochilus acutirostris is an egg-scatterer with no parental care. Eggs are released over gravel, cobble or rocky substrate in fast-running water and receive no subsequent attention from either parent. In monsoon-driven river systems of the Western Ghats, spawning in large barbs is typically cued by the onset of the southwest monsoon (June–September), which brings cooler temperatures, rising flow and higher turbidity — stimuli that trigger gonadal development and spawning migration in many cyprinids of the region.
Neolissochilus acutirostris has not been maintained or bred in captivity; its large adult size, requirement for cool, fast, highly oxygenated water, and recent description mean it remains unknown in the aquarium hobby. Breeding observations therefore exist only by analogy with related large hill-stream barbs.
In the aquarium
Neolissochilus acutirostris is not an aquarium species and is unlikely to become one in the near term. Adults of the holotype size class — over 9 in standard length — would require very large facilities providing cool, fast-moving, highly oxygenated water replicating the hill-stream conditions of the Cauvery headwaters. The species has not appeared in the aquarium trade and no captive husbandry data exist.
Its closest relatives in the hobby context are other large mahseer-type barbs, which share the need for strong filtration, high flow rates, cool temperatures (ideally below 77 °F), and spacious tanks with robust decor. For the foreseeable future, Neolissochilus acutirostris is of interest primarily as a subject of conservation biology and ichthyological research rather than as a fish for aquarists.
Conservation
Neolissochilus acutirostris has not been assessed by the IUCN Red List. Described only in 2017 from a limited range in the Cauvery River drainage of Karnataka, it is a Western Ghats endemic subject to the range of pressures that threaten freshwater biodiversity across that globally recognised hotspot. The Western Ghats river systems face habitat degradation from deforestation, dam construction, irrigation extraction, sand mining, and agricultural runoff — pressures that disproportionately affect hill-stream species with restricted, specialised niches.
The Cauvery basin in particular has been heavily modified by water infrastructure over the past century; large stretches of its mainstream and tributaries are regulated. Whether the specific streams in Kodagu where the type series was collected remain intact is not confirmed by the available data. Given the very limited known range and the ongoing degradation of Western Ghats hill-stream habitats, a precautionary view would treat this species as potentially threatened pending a formal IUCN assessment.