Taxonomy & naming
Desmopuntius mahakamensis was described by Harefa, Haryono and Gustiano in 2025 in the journal ZooKeys (volume 1256, pp. 371–391), based on material from the Mahakam River of East Kalimantan, Borneo, Indonesia. The description rested on an integrative taxonomy framework, combining traditional morphometric and meristic analysis with COI DNA barcoding to establish the species as distinct from other known Desmopuntius and stripe-bodied Bornean barbs.
The genus Desmopuntius was established as part of the sweeping reclassification of Asian barbs that followed the landmark revision of Pethiyagoda et al. (2012), which dismantled the old catch-all genus Puntius. Members of Desmopuntius are laterally striped barbs of Sundaland and the surrounding region. Prior to the formalisation of Desmopuntius, many of its members would have been placed under Puntius; the Catalog of Fishes (Eschmeyer, CAS) is the authority for the current valid name and genus placement. The species belongs to subfamily Smiliogastrinae within the family Cyprinidae.
Morphology
D. mahakamensis is a small, moderately elongate barb reaching a maximum recorded size of 3 in in standard length. The most striking feature is its pattern of five to six solid black longitudinal stripes on the flanks, together with an axial streak — a combination that distinguishes it from the simpler-banded barbs of the region. The lateral line carries 26 to 27 scales (mode 26); predorsal scale counts run 9 to 11; gill rakers number 9 to 11; and vertebral count is 29. The anal fin carries 5.5 fin rays in the standard formulation.
These meristic values, together with the distinctive stripe count and the presence of the axial streak, formed the primary morphological basis for separating this species from congeners during the original description. The overall body form is typical of the genus: moderately compressed, with a blunt snout and the two pairs of barbels characteristic of Desmopuntius.
Habitat
The type locality is the Mahakam River system of East Kalimantan, in the eastern portion of the island of Borneo. The Mahakam is one of Kalimantan's major river systems, draining a large basin that encompasses the Middle Mahakam wetland complex — a network of oxbow lakes, floodplain swamps and tributary rivers of considerable ecological significance for freshwater biodiversity.
FishBase records a temperature of approximately 77 °F and a neutral pH of around 7 for the species, consistent with the mixed lowland river and floodplain habitats of this part of Borneo. Like other Desmopuntius from Sundaland, the Mahakam striped barb is a benthopelagic freshwater species associated with the warmer, lower-gradient portions of the river system rather than cold montane streams. The Middle Mahakam lakes and wetlands provide a mosaic of still and slow-moving habitats that support a rich cyprinid fauna.
Feeding
No detailed dietary study of D. mahakamensis has been published. By analogy with other small Desmopuntius and with stripe-bodied Bornean barbs generally, the species is presumed to be an opportunistic omnivore, taking small invertebrates — insect larvae, microcrustaceans and worms — alongside algae, fine plant material and organic detritus encountered along the substrate and in the water column.
In the aquarium, stripe-bodied Desmopuntius typically accept a wide range of prepared foods readily and benefit from supplementation with live or frozen small invertebrates. Given the species' benthopelagic habit, sinking foods that reach the lower water column are likely to be taken readily.
Mating
Desmopuntius mahakamensis has not been studied in terms of reproductive behaviour in the wild or in aquaria. As a member of the cyprinid family and the barb lineage, it is expected to be an egg-scattering, non-guarding spawner — the reproductive mode universal among barbs. In related species, a ripe male pursues a gravid female through vegetation or over the substrate, and eggs and milt are released together in brief, pressing encounters.
There is no pair bond and no territory maintained beyond the act of spawning itself. Eggs are adhesive and settle among plants or substrate debris. As is typical for barbs, no parental care is provided and adults will consume eggs given the opportunity.
Breeding
No captive breeding records for D. mahakamensis are available in the literature at the time of writing. The species was described only in 2025 and has not yet entered the aquarium trade in any established way. Breeding protocols developed for other similarly sized stripe-bodied Desmopuntius — such as D. hexazona or D. johorensis — are likely to be applicable: a conditioning period on live or frozen foods, a separate spawning tank with soft slightly acidic water, fine-leaved plants or a spawning mop, and removal of adults after egg deposition to prevent predation on the spawn.
Fecundity, incubation time and larval requirements remain undocumented for this species. Hobbyists keeping this barb should treat it as an egg-scatterer with no parental care and plan accordingly.
In the aquarium
Desmopuntius mahakamensis is a very recently described species and is not currently established in the aquarium trade. Its striking multi-stripe pattern — five to six bold longitudinal black stripes — would make it an attractive subject for hobbyists interested in Bornean cyprinids, and it falls within a size range (under 3 in SL) manageable in a modestly sized aquarium.
Pending any dedicated captive experience, the general Desmopuntius template applies: a well-filtered tank with slightly acidic to neutral water around 75–79 °F, soft to moderately hard conditions reflecting the Mahakam basin's lowland river character, and a shoal of conspecifics to allow natural social behaviour. Like other stripe-bodied barbs the species is likely to be active and gregarious. Its current rarity in the hobby means that any keeper working with this fish would be contributing genuinely novel captive husbandry data.
Conservation
Desmopuntius mahakamensis has not been evaluated by the IUCN Red List; the species was described in 2025 and is too recent for a formal conservation assessment. Its known range is centred on the Mahakam River system of East Kalimantan, a basin that faces significant and well-documented environmental pressures. The Borneo interior has experienced accelerating deforestation, large-scale land conversion for oil palm and coal mining, and the associated consequences of sedimentation, water quality degradation and hydrological disruption in river systems.
The Middle Mahakam wetland complex, which forms part of this species' presumed habitat, has been identified in the scientific literature as an ecologically important but threatened lowland freshwater system. For a narrow-range endemic known only from the Mahakam basin, these habitat pressures are a legitimate concern even in the absence of a formal IUCN threat assessment. Baseline surveys to establish the species' range and abundance across the Mahakam system would be a prerequisite for any future evaluation.