Taxonomy & naming
Oreonectes acridorsalis was described by Lan in 2013 from a cave near Bamu Town, Tian'e County, in the Hongshui River drainage of Guangxi, China. It was placed in Oreonectes, a genus of small, often cave-associated stone loaches within the family Nemacheilidae, the largest family of true loaches and the group that includes the cool-water "stone" or "brook" loaches of Eurasia.
The genus-level picture for China's cave nemacheilids has shifted since 2013: subsequent morphological and molecular work has moved this species toward a newly erected genus, Karstsinnectes, alongside other karst-cave Oreonectes-like loaches, and the species has also appeared in some databases under the synonym Troglonectes acridorsalis. This article follows the original combination, Oreonectes acridorsalis, as directed; readers researching the species further afield should also check under Karstsinnectes acridorsalis and Troglonectes acridorsalis, since sources use different combinations depending on their date.
Morphology
As a member of Nemacheilidae, Oreonectes acridorsalis has the family's typical elongate, sub-cylindrical body and small size — the largest recorded specimen (an unsexed male) measured only 2 in standard length. Like other stone and brook loaches it is essentially scaleless in appearance, with skin that offers little protection against medication or rough handling.
Detailed morphological description is limited in the material reviewed here, but cave-dwelling relatives in this group typically show the classic troglobitic suite — reduced pigmentation and reduced or vestigial eyes — as adaptations to a lightless cave-stream existence. Data on this specific species' morphology beyond size and type-locality is sparse, and readers should treat any claim about eye or pigment reduction in this particular species as inferred from its cave habitat and relatives rather than confirmed in the sources reviewed.
Habitat
This species is known only from cave streams in karst limestone terrain near Bamu Town, Tian'e County, Guangxi, China, in the Hongshui River system, at around 938 ft elevation. It appears to be a single-locality endemic, restricted to the specific cave system in which it was first collected and described.
The water is expected to be cool to mild, clear, fast-flowing and well-oxygenated, consistent with both its karst cave-stream setting and the broader pattern in Nemacheilidae, whose stone and brook loaches are cool-water dwellers of clear, oxygen-rich streams rather than warm, still, blackwater habitats. Substrate is cave limestone and gravel. Beyond this, detailed habitat data (precise temperature and pH readings, seasonal variation) has not been recorded for this species and should be treated as data-sparse.
Feeding
Oreonectes acridorsalis is presumed to be a benthic micro-predator, in keeping with the great majority of Nemacheilidae, foraging over the stream bed for small invertebrates and insect larvae. In a lightless cave-stream environment, food inputs are likely to be limited and irregular — cave-adapted fish generally rely on whatever organic material and small invertebrate life washes into or persists within the cave system.
No aquarium feeding data exists for this species, since it is not established in the hobby. Based on its family and habitat, any captive individual would be expected to take small live or frozen foods (bloodworm, small crustaceans) taken off the substrate, rather than surface flake.
Mating
No courtship or spawning behaviour has been documented for Oreonectes acridorsalis. Nemacheilidae as a family are egg-scatterers rather than pair-forming or cave-guarding spawners, releasing eggs over gravel and stones in flowing water with no parental care, but the specifics of how — and whether — this triggers in a permanently dark cave-stream environment (versus surface stream, seasonal cues like day length or monsoon flow) have not been studied for this species.
Breeding
This is a data-sparse, single-locality cave species with no recorded aquarium or captive spawning. Consistent with its family, the expected mode is an egg-scatterer over gravel and stones in fast water, with no parental care. There is no evidence this species has ever been bred in captivity, and given its lack of presence in the aquarium trade, breeding data is unlikely to exist at all. The honest statement is simply that breeding biology is unknown beyond the general pattern of its family.
In the aquarium
Oreonectes acridorsalis is not a hobby fish. It has not been reported in the aquarium trade in the sources reviewed here, and as a cave-restricted endemic from a single karst system in Guangxi, it is not realistically available to keepers. Its natural history — a small, cool-to-mild, fast-flowing, well-oxygenated cave stream — gives a broad sense of what any hypothetical captive care would demand: clear, highly oxygenated, filtered water and a dim or dark environment, far from the standard community tank.
As with other near-scaleless Nemacheilidae, any captive individual should be presumed sensitive to copper and full-strength medications, warranting caution and reduced dosing if disease treatment were ever needed.
Conservation
Oreonectes acridorsalis has not been evaluated on the IUCN Red List. As a species known from a single cave system in Guangxi, China, it fits the broader pattern among karst-cave Nemacheilidae of being a narrow-range endemic vulnerable in principle to any disturbance of its specific cave-stream habitat — groundwater pollution, quarrying, or hydrological changes to the karst system — though no formal population assessment or documented threat data exists for this species. It is not part of the aquarium trade, so trade pressure is not a relevant conservation factor here; the honest position is that its conservation status is simply unknown.