Taxonomy & naming
Rasbora kluetensis was formally described by Lumbantobing (2010) in Copeia 2010(4):644–670, as part of a broader revision of the Rasbora trifasciata species group — a cluster of slender, small-bodied rasboras distributed across the Sunda shelf. The Catalog of Fishes (Eschmeyer, CAS) records the valid combination as Rasbora kluetensis Lumbantobing, 2010. No subsequent name changes or synonymies are on record for this species.
The species epithet kluetensis refers to the Kluet River drainage (also rendered Klut or Kluet), located in Aceh Selatan (South Aceh) district, northwestern Sumatra, which is the sole known locality. Within the trifasciata group, Lumbantobing distinguished R. kluetensis on the basis of its Type E cephalic sensory tubercles — conical, microridged structures used as a character system in diagnosing members of this complex — as well as meristic and morphometric characters setting it apart from sympatric congeners including R. api, R. jacobsoni, and R. cf. sumatrana.
The broader genus Rasbora has undergone considerable reshaping since the 1990s. Genera including Boraras, Trigonopoma, Brevibora, Kottelatia and Rasboroides were carved out of what was once a broadly circumscribed Rasbora, and Microrasbora and Trigonostigma (for the harlequin-type species) were erected or redelimited by Kottelat and Witte (1999). R. kluetensis has remained in Rasbora under all post-description treatments and is not one of the species affected by those generic splits.
Morphology
Rasbora kluetensis is a small, slender cyprinid reaching a maximum recorded standard length of approximately 1.5 in. As a member of the trifasciata group it has the typical rasbora body plan — elongate and laterally compressed, with a relatively small head, terminal to slightly upturned mouth, and a forked caudal fin. The species-level diagnosis rests partly on the conical, microridged (Type E) cephalic sensory tubercles and on a combination of scale counts, body proportions, and lateral-line scale formulae that distinguish it from its close relatives in the same drainage.
Detailed colouration notes are not extensively documented in the available literature for this species, and the general appearance is that of a moderately marked small rasbora. FishBase categorises it as benthopelagic, suggesting it occupies the mid-water and lower zones of the water column rather than being a strict surface fish. Specific fin-ray and lateral-line counts from the original description provide the definitive morphological reference; secondary sources on aquarium-kept specimens are currently lacking for this species.
Habitat
Rasbora kluetensis is known exclusively from the Kluet River basin in northwestern Sumatra, making it one of many single-drainage endemics among the rich cyprinid fauna of the Sunda shelf. The Kluet River drains the southern slopes of the Barisan mountain range in Aceh Selatan, flowing to the Indian Ocean coast, and supports a diverse rasbora community: R. kluetensis occurs there alongside R. api, R. jacobsoni, and R. cf. sumatrana.
No formal water-chemistry data for R. kluetensis collection sites are captured in the available sources. As a Sumatran lowland river species on the western coast of the island, the surrounding landscape is tropical humid forest grading into the foothills, and the river water is likely soft and moderately acidic — broadly typical of Sundaland river systems — though this should be treated as a working inference rather than a confirmed figure. FishBase records the species as a freshwater tropical benthopelagic fish with no specific pH or temperature parameters listed for the collection sites.
Feeding
FishBase assigns Rasbora kluetensis a trophic level of 3.1 ± 0.4, placing it in the lower micropredator range — a small-organism feeder taking invertebrates, small crustaceans, insect larvae, and similar prey from the water column. This is consistent with the feeding ecology of the wider Rasbora trifasciata group and with that of small cyprinids generally in Sundaic rivers.
No detailed dietary study specific to this species has been published. In captivity, small rasboras of similar size and ecology are readily fed on high-quality micro pellets or crushed flake, with live and frozen foods such as Daphnia, micro worms, and baby brine shrimp used to maintain condition — guidance that can be applied provisionally to R. kluetensis, though aquarium observations on this species remain sparse in the published literature.
Mating
Rasbora kluetensis, as a member of the genus Rasbora, is an egg-scattering, non-guarding spawner. No specific reproductive observations for this species appear in the published or hobby literature at the time of writing. By inference from its closest relatives in the trifasciata group and from the broader biology of the genus, spawning likely follows the typical rasbora pattern: a driving male pursues a gravid female through vegetation or over the substrate, and eggs and milt are released together without nest construction or territory defence.
There is no parental care. Eggs are scattered — typically adhesive or weakly adhesive — over fine-leaved plants, submerged roots or the bottom, where adults will consume them given the opportunity. Spawning in Sundaic rasboras is often seasonal, associated with rainfall and water-level changes in the rivers, though the precise reproductive timing for this Kluet River endemic has not been documented.
Breeding
No captive breeding accounts for Rasbora kluetensis are recorded in the aquarium literature, reflecting the fact that this recently described single-basin Sumatran endemic has not entered the ornamental trade in meaningful numbers. The general principles applicable to closely related trifasciata-group rasboras would apply: a separate, well-planted spawning tank with fine-leaved plants or a spawning mop, soft and slightly acidic water, and conditioning of the adults on live and frozen foods prior to introduction.
Eggs are expected to be small, scattered, and adhesive; the adults should be removed after spawning to prevent predation on the eggs. Hatch times and larval development are not specifically documented for this species. Any captive breeding observations would be of genuine scientific and conservation interest given the species' restricted natural range.
In the aquarium hobby, the species is essentially unavailable as of 2026, and breeding data remain a gap in the literature. Facts.breeding parameters are set to reflect the inferred egg-scattering mode common to all Rasbora.
In the aquarium
Rasbora kluetensis is not an established aquarium fish. It has not entered regular trade channels and no specific husbandry accounts appear in the hobby literature; the species is known primarily from ichthyological specimens and the original description. Any specimens that do reach aquarists would presumably be treated similarly to other small, single-locality Sundaic rasboras: a mature, well-filtered aquarium with soft, slightly acidic water, gentle flow, subdued lighting, fine-leaved planting, and a peaceful community of similarly sized fishes.
Given its restricted range and single known basin, casual or unregulated collection from the wild would be inadvisable. Should captive populations be established for conservation or study purposes, close attention to water quality and social grouping — rasboras are shoaling fish and fare poorly in isolation — would be essential. Aquarists encountering this species should document observations carefully, as published data on its behaviour and requirements are currently almost entirely absent.
Conservation
Rasbora kluetensis was assessed as Least Concern (LC) on the IUCN Red List in 2019 (IUCN 2022.2), a designation that reflects the absence of documented population decline rather than a necessarily secure situation for a single-basin endemic. The entire known range falls within one river system — the Kluet River drainage of South Aceh, northwestern Sumatra — meaning any significant degradation of that basin could affect the species across its entire range simultaneously.
Sumatra has lost a substantial proportion of its lowland forest cover to palm oil plantations, logging, and agricultural conversion over recent decades, and river systems in Aceh province have not been immune to these pressures. The Kluet River basin sits adjacent to the Gunung Leuser ecosystem, one of the last large blocks of intact Sumatran forest, but peripheral drainages can still experience agricultural encroachment and sedimentation. R. kluetensis shares its system with several congeners, suggesting the habitat remains broadly intact at present, but the LC status should be revisited as survey data from the region are updated. Single-basin endemics of the Sunda shelf are among the fish fauna most vulnerable to catchment-scale habitat change.