Taxonomy & naming
Rasbora meinkeni was described by Lieven Ferdinand de Beaufort in 1931, with the type locality recorded from the Lake Laut Tawar system in Aceh, northern Sumatra. The Catalog of Fishes (Eschmeyer, the authority for valid names) maintains the species in the genus Rasbora under this original combination.
The genus Rasbora has undergone considerable revision over the past three decades. Kottelat and Witte (1999) and subsequent workers carved out several satellite genera — Boraras, Trigonopoma, Brevibora, Trigonostigma, and others — from what was once a broadly defined Rasbora. Rasbora meinkeni, however, has remained within the core Rasbora sensu stricto throughout this taxonomic reshuffling, and there is no indication in the literature of a proposed transfer to another genus. FishBase confirms the current valid name as Rasbora meinkeni de Beaufort, 1931.
Morphology
Rasbora meinkeni is a slender, streamlined cyprinid reaching a recorded maximum of 1.5 in standard length — a size typical for small rasboras. Like most members of the genus it has a moderately compressed body, a subterminal or slightly upturned mouth, and a forked tail. Specific published descriptions of colouration are sparse in the available literature; the species is presumed to share the typical small Rasbora body plan of a pale silvery or yellowish flank, possibly with a dark lateral stripe or mid-body markings, though data on this point are limited.
Sexual dimorphism is not well documented for this species. In related small rasboras, females are generally deeper-bodied and more rounded in the abdomen when gravid, while males are slimmer. Given the paucity of species-specific morphological literature, hobbyists should treat published descriptions of related Sumatran rasboras as a guide rather than a confirmed match.
Habitat
Rasbora meinkeni is freshwater and benthopelagic, recorded from Lake Laut Tawar and its tributary rivers in the Gayo Highlands of Aceh province, northern Sumatra. FishBase also notes a probable extension to the Malay Peninsula, though this remains to be confirmed. Lake Laut Tawar is a highland lake sitting at roughly 1,656 ft above sea level, notably cooler and clearer than the lowland peat-swamp systems that characterise much of Sundaland.
No species-specific temperature, pH, or hardness data are available in the published record for this species. As a highland Sumatran lake fish, it likely inhabits clear, moderately cool freshwater rather than the warm, highly acidic blackwaters of the Sumatran lowlands. Its classification as benthopelagic suggests it ranges through the water column and over or near the substrate, probably in association with other small cyprinids in the lake's open and vegetated margins.
Feeding
No species-specific diet data are available in the literature for Rasbora meinkeni. As a small cyprinid in the broader Rasbora assemblage, it is most likely an omnivorous micropredator in the wild, feeding on small aquatic invertebrates — insect larvae, microcrustaceans, and similar prey — alongside algae, plant material and organic detritus, in keeping with the feeding ecology typical of the genus.
In an aquarium setting, small rasboras of comparable size and habit generally accept quality micro-pellets and fine flake foods, with live and frozen items such as daphnia, micro-worms, and newly hatched brine shrimp used to maintain condition. Variety in diet supports good colour and reproductive readiness.
Mating
Rasbora meinkeni is an egg-scattering, non-guarding spawner. Like the great majority of rasboras and danios, it produces no nest and exercises no parental care. In natural conditions spawning is likely triggered by seasonal changes in water level, temperature, or light, consistent with the monsoonal and highland-lake seasonality of its Sumatran range.
Courtship follows the pattern typical of the group: a conditioned male pursues a gravid female closely through vegetation or open water, the pair releasing eggs and milt together in brief, repeated passes. No pair bond is formed. The adults will eat their own eggs once spawning ends, so separation of parents from the spawn is standard practice.
Breeding
Breeding Rasbora meinkeni in captivity has not been widely documented in the hobby literature, reflecting its relative rarity in the trade. As an egg-scatterer in the Rasbora mould, the general approach for small rasboras applies: a well-conditioned group is placed in a separate, shallow breeding tank furnished with fine-leaved plants, Java moss, or a spawning mop over a mesh or marbles that allow eggs to sink out of the adults' reach.
A mild drop in temperature followed by a partial water change with slightly cooler, soft water can simulate the seasonal cue and encourage spawning at dawn or in the morning light. Parents should be removed after spawning. Eggs of small rasboras typically hatch in 24–72 hours depending on temperature, and the free-swimming larvae take infusoria or commercial fry foods initially before graduating to newly hatched brine shrimp. No parental care of any kind is given at any stage.
In the aquarium
Rasbora meinkeni is not widely encountered in the aquarium hobby, and commercially available individuals are rarely seen outside specialist importers dealing in Sumatran endemics. When kept, its care requirements are presumed to follow those of other small, highland Sumatran rasboras: a clean, well-oxygenated aquarium with moderate current, soft to moderately soft water, and a temperature somewhat lower than standard tropical tanks — reflecting its origin in the cool highland waters of Lake Laut Tawar.
As a shoaling species it should be kept in groups of at least six to express natural behaviour and minimise stress. Suitable companions are other peaceful small cyprinids or similarly sized, undemanding fishes. Dense planting along the sides and back, with open swimming space in the mid-water, suits the genus well. Its small adult size makes it appropriate for smaller aquariums when maintained in a proper school.
Conservation
Rasbora meinkeni is assessed as Least Concern (LC) on the IUCN Red List, with a 2019 assessment noting high population resilience and a minimum population doubling time of under 15 months. FishBase corroborates the LC status and records low vulnerability to fishing pressure (a vulnerability index of 10 out of 100).
Despite its current LC standing, the species warrants attention given its narrow endemic range centred on a single highland lake system in Aceh, Sumatra. Lake Laut Tawar and its tributaries are subject to ongoing pressure from human settlement, agricultural runoff, and introduced species — threats that affect many single-basin endemic fishes in Sumatra even where populations currently appear stable. Any significant degradation of the lake's water quality or catchment hydrology could quickly affect a species whose entire known range fits within a comparatively small highland basin.