Taxonomy & naming
Neonoemacheilus peguensis was described by the Indian ichthyologist Sunder Lal Hora in 1929, hence the parenthetical authority. It sits in Nemacheilidae, the stone and brook loaches — the largest family in the loach superfamily Cobitoidea, encompassing hundreds of small, often narrowly endemic species across Eurasia. The genus Neonoemacheilus is one of several segregated over the decades from the old, overly broad Nemacheilus/Noemacheilus catch-all that once absorbed much of this family; as with many Nemacheilidae, older literature may still refer to this or related species under Noemacheilus or Nemacheilus, but the current valid combination follows the Catalog of Fishes.
The species epithet peguensis refers to Pegu (now Bago), the region of Myanmar that gave the type locality its name. It remains a little-studied taxon even within its own data-poor family, with no widely available redescription or revision noted in the sources consulted here.
Morphology
As a member of Nemacheilidae, Neonoemacheilus peguensis has the characteristic stone-loach build: an elongate, sub-cylindrical body, a flattened belly suited to gripping the bottom in current, and a small, low-slung mouth with fine barbels for finding food among gravel. Nemacheilids are near-scaleless or have very small, deeply embedded scales, leaving the skin effectively naked — a trait that matters for disease sensitivity rather than appearance.
Detailed morphometric data (maximum length, fin-ray counts, colour pattern) for this species were not found in the sources available for this profile; published accounts of Neonoemacheilus peguensis are sparse, consistent with its status as a narrow-range hill-stream endemic that has drawn little study since its original description.
Habitat
This species is known from streams in the Pegu (Bago) Hills of Myanmar (Burma), a highland drainage system in the country's south-central region. Like other stone and brook loaches, it lives in fast-flowing, cool, clear water over gravel and stone substrate, in streams that carry high dissolved oxygen from their steady current.
Its distribution appears restricted to this Myanmar highland system, and no evidence in the available sources suggests a wider range. That kind of single-drainage endemism is typical across Nemacheilidae, where many species are known from one stream system or a small cluster of them.
Feeding
Neonoemacheilus peguensis is a benthic micro-predator, foraging over the stream bed for small invertebrates, insect larvae and crustaceans — the standard diet of a fast-water stone loach. In an aquarium setting this profile implies a fish that wants small live or frozen foods delivered near the bottom, and that may largely ignore flake or foods left floating at the surface.
No aquarium feeding records specific to this species were found; the diet described here follows the general pattern documented for Nemacheilidae and the habitat this species occupies.
Mating
No courtship or spawning behaviour has been documented for this species in the sources available. Stone and brook loaches in general are egg-scatterers rather than pair-forming or guarding species, releasing eggs over gravel and stones in flowing water without preceding pair-bond behaviour of the kind seen in cichlids or many catfish. Nothing more specific can be said for Neonoemacheilus peguensis without speculating beyond what is documented.
Breeding
Consistent with its family, Neonoemacheilus peguensis is presumed to be an egg-scatterer, broadcasting eggs over gravel and among stones in flowing water with no parental care afterward. No confirmed captive-breeding record for this species was found, and its breeding behaviour in the wild is poorly documented even in the scientific literature — typical for a narrow-range Nemacheilidae endemic that has drawn little research attention since its description.
It should be considered, for all practical purposes, a species that is not bred in the aquarium. Anyone encountering it in the trade should not expect to replicate reproduction without first solving the basic husbandry challenge of a genuinely data-sparse, cool-water hill-stream fish.
In the aquarium
Neonoemacheilus peguensis is essentially unknown in aquarium keeping, and this profile should be read as an inference from its family and habitat rather than a tested care sheet. Coming from fast, cool, highly oxygenated hill streams, it would need strong water movement, high dissolved oxygen, a gravel-and-stone substrate, and cooler water than most tropical community fish — closer to 18–24 degrees Celsius than to a standard heated tropical tank — with neutral to slightly acidic, soft-to-moderate water chemistry.
Like other nemacheilids it is likely near-scaleless and therefore sensitive to copper-based medications and full-strength treatments; any medicating should start conservatively. As a small benthic predator it will want sinking live or frozen foods rather than flake. Given the near-total absence of hobby documentation, anyone who does obtain this fish should treat husbandry as exploratory and prioritise stable, cool, well-oxygenated, flowing water above all else.
Conservation
Neonoemacheilus peguensis has not been evaluated by the IUCN Red List, so it carries no formal conservation status here — recorded honestly as Not Evaluated rather than guessed at. Its apparent restriction to streams in Myanmar's Pegu (Bago) Hills places it among the many narrow-range Nemacheilidae endemics whose conservation status is essentially undocumented, a data gap rather than evidence of either safety or risk.
As with many such restricted hill-stream endemics, habitat pressures typical of the region — deforestation, water extraction and stream modification — would be the plausible long-term risks to a single-drainage species, though no assessment or targeted study confirming this was found for Neonoemacheilus peguensis specifically.