Taxonomy & naming
Schistura larketensis was formally described in 2017 by Choudhury, Mukhim, Basumatary, Warbah and Sarma in the journal Zootaxa, based on specimens collected from Krem Khung, a limestone cave near Larket village in the East Jaintia Hills district of Meghalaya, India. It belongs to the family Nemacheilidae, the stone and brook loaches — by far the largest loach family, and one still being actively revised as taxonomists sort the old catch-all genera Nemacheilus and Noemacheilus into narrower, better-defined groups such as Schistura, Triplophysa and Barbatula. The Catalog of Fishes lists it under the genus Schistura, and that placement is followed here.
The species epithet larketensis refers directly to Larket, the village adjacent to the type-locality cave. The authors distinguished it from its closest known relative, S. papulifera, by a suite of small but diagnostic characters: a smooth (non-papillate) ventral head surface, a cylindrical rather than flattened axillary pelvic lobe, and a specific count of three supratemporal canal pores. As a species known from a single cave system and formally recognised for less than a decade, it has not yet accumulated a body of follow-up literature — most of what is known still traces back to the original description.
Morphology
Schistura larketensis is a small, slender nemacheilid loach built on the same general plan as its stream-dwelling relatives — an elongate, cylindrical body, a ventrally flattened head, and the barbels typical of the genus for finding food by touch and taste. What sets it apart is troglomorphy: the suite of changes cave animals evolve when they stop needing to see. Its eyes are absent or reduced to non-functional vestiges, an adaptation shared with other obligate cave fish worldwide, from Mexican blind tetras to cave-dwelling loaches elsewhere in Asia. Losing functional eyes is a common outcome in permanently dark habitats, where vision offers no advantage and the tissue and energy cost of maintaining it is better spent elsewhere.
Like other members of its family, S. larketensis is a scaleless or near-scaleless fish, a trait that in surface-dwelling loaches translates into sensitivity to medication — though for a fish that will not be kept in an aquarium, the more relevant point is what the trait says about its physiology as a stream-adapted animal that has moved permanently underground. Detailed measurements and a full size range were not the focus of the primary description, which prioritised the diagnostic characters separating it from S. papulifera; precise size data for the species is sparse.
Habitat
The known range of Schistura larketensis is a single cave: Krem Khung, near Larket village in the East Jaintia Hills of Meghalaya, in India's northeast. The type specimens were collected from a stagnant pool roughly 1.5 metres deep, situated about 500 metres inside the cave passage from the entrance — well beyond any reach of daylight. This is not a fast-flowing hillstream habitat like many of its Schistura relatives occupy on the surface; it is a still, dark, presumably nutrient-poor cave pool, fed by groundwater percolating through Meghalaya's extensive limestone karst.
Meghalaya holds some of the longest and most biologically rich cave systems in Asia, and its karst has produced a small but growing list of troglobitic (cave-obligate) fish and invertebrates. Because S. larketensis is known only from this one cave pool, its entire population depends on the health of a single, geographically tiny, hydrologically connected system — any disturbance to water quality, flow or the cave environment itself has no other refuge to fall back on.
Feeding
No dietary study has been published for Schistura larketensis, and the primary description does not report gut contents or feeding observations — this is genuinely data-sparse territory. What can be said comes from its family and its habitat: nemacheilid loaches in general are benthic micro-predators and opportunistic foragers, using barbels to detect small invertebrates, insect larvae and organic material on and in the substrate. In an eyeless cave specialist, that touch-and-taste-driven foraging strategy would matter even more, since vision plays no part in locating food in permanent darkness.
Cave pools like the one S. larketensis inhabits typically have far less food input than surface streams — no photosynthesis, no leaf litter fall from streamside vegetation, and only whatever organic matter washes or drips in from outside or is carried by other cave fauna such as bats and invertebrates. A slow metabolism and an ability to subsist on sparse, irregular food are plausible traits for an animal in this niche, but they have not been documented for this species specifically, and no diet has been confirmed in the literature reviewed here.
Mating
Nothing has been published on courtship, sexual dimorphism or spawning behaviour in Schistura larketensis. The 2017 description is a taxonomic paper focused on establishing the species as new and diagnosing it from its closest relative; it does not report breeding observations, and no subsequent field or captive study appears in the sources available here. This is unsurprising for a fish known from a single, hard-to-access cave pool studied by very few researchers.
Breeding
As with mating behaviour, no breeding biology has been documented for this species — there is no record of it being bred, or even observed spawning, in the wild or in captivity. Based on its family, the honest expectation is that it would be an egg-scatterer with no parental care, in keeping with nemacheilid loaches generally, but this is an inference from its relatives rather than a confirmed fact about S. larketensis itself. It should not be assumed to guard a cave the way some unrelated gobies do, nor to brood eggs in any way — cave-dwelling has not been shown to change the family's egg-scattering reproductive mode in any documented case. Given the species' extreme habitat and rarity, breeding data here is essentially absent, and that gap should be stated plainly rather than filled with speculation.
In the aquarium
Schistura larketensis is not an aquarium fish, and it is not traded. It is known only from a single cave pool in Meghalaya, has no established husbandry record, and — as an eyeless obligate cave specialist adapted to permanent darkness, still water and presumably a very stable, low-nutrient environment — would be an extraordinarily poor candidate for captive care even if specimens were ever available, which they should not be. There is no evidence of it appearing in the aquarium trade, and none is expected given its restricted, cave-locked distribution.
Its value to this atlas is as an illustration of just how far the stone-and-brook loach family (Nemacheilidae) has diversified — from the fast-flowing, oxygen-rich hillstreams that host most Schistura species to the total darkness of a limestone cave — and as a case study in how narrowly a single species' entire existence can be tied to one physical place.
Conservation
Schistura larketensis has not been formally assessed by the IUCN Red List; it is recorded here as Not Evaluated (NE) rather than assigned a guessed category. Given that it was described only in 2017 from a single cave system, and that formal assessments for narrow-range, recently described cave fish often lag well behind description, an NE status reflects a genuine absence of evaluation rather than any indication of low concern.
The conservation stakes for a single-cave endemic are inherently high: this is a species with no known population outside Krem Khung, in a region — Meghalaya's East Jaintia Hills karst — subject to pressures from limestone quarrying, cave tourism, and broader land-use change across its catchment. The species' popular coverage (including the Mongabay report cited below) explicitly frames it as part of a fragile cave ecosystem in need of conservation attention. There is no trade pressure on this species; the risks it faces, if any, are habitat- and site-integrity risks to the one cave it calls home, not collection for the aquarium hobby.