Taxonomy & naming
Schistura klydonion was described in 2017 by the Swiss ichthyologist Maurice Kottelat, published in the Raffles Bulletin of Zoology (volume 65, pages 341–356) together with a second new species from the same river system, Schistura colossa. Both were collected from the Xe Namnoy, a tributary system draining the Bolaven Plateau in southern Laos, an upland basalt plateau that has yielded a run of newly described Nemacheilidae in recent decades as ichthyologists have surveyed its headwater streams more closely. The Catalog of Fishes, the standing authority for valid fish names, lists the species under this original combination with no subsequent synonymy.
The genus Schistura is itself a product of the repeated taxonomic reshuffling that has affected Cobitoidea over the past half-century: many species once lumped into the old catch-all genera Nemacheilus or Noemacheilus have since been redistributed among Schistura, Triplophysa, Barbatula and other genera on the basis of fin-ray counts, lateral-line development and other characters. Schistura klydonion was described directly into the modern genus and has no earlier name to reconcile.
The specific epithet klydonion derives from the Greek for a small wave, ripple or undulation, referring to the wavy pale zigzag line that runs along the fish's side between its two rows of dark markings — a naming choice typical of Kottelat's practice of drawing epithets directly from a diagnostic feature of the colour pattern.
Morphology
Schistura klydonion is a small, slender stone loach; the paratype specimen (CMK 23320) measured 3 in standard length, in the typical size range for the genus. As in other Nemacheilidae, the body is elongate and only lightly built, with the near-scaleless, thin-skinned integument characteristic of the family — a trait that matters for aquarium keepers because it leaves these fish unusually sensitive to medications and to poor water quality.
The diagnostic colour pattern is a midlateral row of 12–21 dark bars alternating with a middorsal row of saddle-like blotches, the two rows separated by the pale, wavy zigzag stripe that gives the species its name. The lips carry sparse, pointed papillae, a detail used alongside the pigment pattern to distinguish it from its close relative S. colossa and other regional Schistura. Like most members of the genus it likely carries the small, erectile suborbital spine typical of Cobitoidea loaches, though the type description's emphasis is on pigment pattern and lip papillae rather than spine morphology specifically.
Habitat
The species is known only from its type locality, the Xe Namnoy river on the Bolaven Plateau in southern Laos — a basalt upland whose streams run clear and fast over rock and gravel substrates, typical Nemacheilidae habitat across mainland Southeast Asia. No dedicated water-chemistry data were published alongside the description, and the species has not been picked up by aquarium-trade or hobbyist sources that might otherwise supply anecdotal readings.
Based on the Bolaven Plateau's elevation and on what is documented for related Schistura in similar upland Lao and Vietnamese streams, the water is best assumed to run cool to moderately warm and well-oxygenated with a fast current — this is an inference from geography and genus, not a measured figure, and should be treated as a starting point rather than a fact. Given the honest absence of source data, this account does not assign firm temperature or pH figures to the species.
Feeding
No feeding study exists for Schistura klydonion specifically. As with other Nemacheilidae, it is reasonable to expect it forages as a benthic micro-predator, picking small aquatic invertebrates, insect larvae and other tiny prey items from among gravel and stones in fast-flowing water — the standard foraging mode across the genus and the family more broadly.
Were the species ever to appear in captivity, that micro-predator biology implies it would need small sinking live or frozen foods (bloodworm, daphnia, brine shrimp) rather than flake, which stone loaches of this kind typically ignore in favour of foods that reach the substrate. This is a reasonable extrapolation from its relatives, not a documented feeding record.
Mating
Nothing has been published on courtship or spawning behaviour in Schistura klydonion. No aquarium or field spawning observations exist, and the type description — focused on diagnosing the species from its holotype and paratype material — does not address reproductive behaviour.
For context, Nemacheilidae as a family are egg-scattering fish with no pair-bonding or courtship display of note; ripe adults release eggs directly into the current rather than forming pairs or defending territory. There is no reason from what is known of the genus to expect this species to differ, but the specific behaviour of S. klydonion itself remains unrecorded.
Breeding
Breeding data for this species does not exist. Stone and brook loaches of the family Nemacheilidae are, as a rule, egg-scatterers: ripe fish release eggs over open gravel or among stones in fast-flowing water and provide no parental care whatsoever — there is no nest-guarding male and no mouthbrooding involved, unlike some other freshwater fish groups. Verified captive spawnings of Schistura species in general are rare, and this particular species has no aquarium-trade history to draw on at all.
Given the complete absence of both a type-locality water-chemistry record and any hobbyist reports, the honest position is that Schistura klydonion has almost certainly never been bred, and possibly never even kept, in an aquarium. Any breeding account here would be invention; the family's known mode — egg-scatterer over gravel, no parental care — is the only thing that can responsibly be stated.
In the aquarium
Schistura klydonion has no known aquarium history. It does not appear in the hobbyist literature, care-guide sites or trade records consulted for this profile, which is unsurprising for a species described in 2017 from a single river system on a remote Lao plateau — it is very unlikely to have entered the ornamental trade at all.
What can be said comes from its genus and family rather than the species itself: Nemacheilidae are near-scaleless fish, so any specimen in captivity would need careful, reduced-dose medication and pristine water quality, and as fast-water stream specialists they would be expected to need cool-to-moderate, well-oxygenated, flowing water rather than a still, warm community tank. Anyone encountering a fish sold or labelled as this species should treat those care parameters as a starting hypothesis only, verify identification carefully, and recognise that essentially no verified husbandry record for it exists.
Conservation
Schistura klydonion has not been formally assessed by the IUCN Red List and is therefore classified as Not Evaluated. As a species known from a single river system — the Xe Namnoy on the Bolaven Plateau — with no published population data, it fits the broader pattern among recently described Nemacheilidae of being a narrow-range stream endemic whose conservation status is simply unknown rather than confirmed to be secure.
The Bolaven Plateau has seen hydropower development and land-use change in recent decades, pressures that can affect the flow and water quality of small tributary systems like the Xe Namnoy, though no study has specifically measured impacts on this species. In the absence of a formal assessment or population monitoring, the responsible position is to flag it as a data-deficient-in-practice, single-locality endemic rather than assert any particular threat level.