Taxonomy & naming
Danio meghalayensis was described by Sen and Dey in 1985 from specimens collected in Meghalaya, the hill-state in north-eastern India. The Catalog of Fishes (Eschmeyer, CAS) records the valid combination as Danio meghalayensis Sen & Dey, 1985. Its placement in the genus Danio — the true danios — is consistent with current taxonomy. GBIF (species ID 2362718) likewise confirms the authority.
Within Danio, the species belongs to a broadly defined assemblage of slim, active stream danios. Danio has absorbed several formerly separate genera over the decades, and the genus boundary with Devario has been debated repeatedly; meghalayensis has not been implicated in those reshufflings. There are no known synonyms in the literature.
Morphology
FishBase records a standard length of 2 in for males and unsexed individuals, with a maximum length of up to 4 in reported — though the larger figure may reflect exceptional or poorly documented records. The species is a typical slim-bodied danio with a slightly upturned mouth suited to surface and mid-water feeding.
Full colour and pattern details are not well documented in the available literature, consistent with its rarity in both wild surveys and the aquarium trade. Like most true danios it is expected to show horizontal striping or patterning along the flank. Females of egg-ready danios are typically deeper-bodied than males; specific dimorphism notes for this species are absent from the published sources.
Habitat
Danio meghalayensis is endemic to Meghalaya state, north-eastern India — a region of steep relief, dense rainfall and fast-draining hill streams. Sources place it at around 1,200 metres (approximately 4,000 feet) elevation, in mountain streams characterised by strong current, high dissolved oxygen and clean substrate.
The water chemistry recorded for the species reflects its upland origin: temperature 61–75 °F (Ball Aquatics gives 64–75 °F), pH 6.0–7.5, and hardness up to 18 dGH. These are softer to moderately hard, slightly acidic to neutral conditions — cooler than typical lowland tropical danios and closer to the subtropical end of the danio spectrum. The species is described as benthopelagic (FishBase), occupying mid-depth to near-surface positions in the water column.
Feeding
Danio meghalayensis is an omnivore with a trophic level of 3.0 (FishBase), consistent with a diet of small invertebrates, insect larvae and organic particles characteristic of fast hill streams. Its upturned mouth suggests active surface and mid-water feeding.
In the aquarium, sources report it accepts granular prepared foods, frozen bloodworms, gel foods, live daphnia and mosquito larvae. The species is described as an aggressive feeder during breeding condition, suggesting it competes actively at mealtimes. A varied diet mixing quality dried and live or frozen items is recommended to maintain condition.
Mating
Like all true danios, Danio meghalayensis is an egg-scattering, non-guarding spawner. There is no nest, no parental bond and no care of offspring. In nature, spawning is likely triggered by seasonal changes in temperature and rainfall in its Meghalayan hill-stream habitat. A driving male pursues a gravid female through vegetation or over substrate, the pair releasing eggs and milt together in brief bursts of activity.
Sources note that the species becomes an aggressive feeder during breeding periods, which may reflect heightened metabolic activity as fish come into spawning condition. The eggs, once scattered over plants, moss or gravel, receive no further attention from either parent.
Breeding
Danio meghalayensis scatters adhesive eggs over fine-leaved plants, moss or substrate; both parents will consume eggs and fry if given the opportunity. Aquarium breeding follows the standard danio approach: a separate spawning vessel with a mesh or marbles over the base, or dense fine-leaved planting to protect eggs from the adults, is recommended. A small drop followed by a slight rise in temperature, simulating the onset of the cool-season rains, may help condition the fish.
FishBase records a high reproductive rate with a minimum population doubling time of fewer than 15 months, indicating the species is a productive breeder under suitable conditions. After spawning, adults should be removed to protect the eggs. Larvae become free-swimming within a few days of hatching and initially take infusoria, then newly hatched brine shrimp as they grow. Detailed breeding accounts in the hobby literature are sparse, consistent with the species' rarity in the trade.
In the aquarium
Danio meghalayensis is genuinely rare in the aquarium trade and represents a specialist's purchase. Sources recommend keeping it in groups of at least six to eight individuals — ideally in a tank of 80 US gal or more — to allow the natural shoaling behaviour that keeps this species confident and reduces stress-related skittishness. Its upland origins demand cool, well-oxygenated water; the 61–75 °F temperature range means it can often be kept without a heater in a temperate room, but water quality and filtration turnover should be high.
The species is an excellent jumper and a securely covered tank is essential. pH 6.0–7.5 and hardness up to 18 dGH suit it well. It is described as a mid-depth and surface dweller, so ample open swimming space along the upper half of the tank is important. Tankmates should be active and robust; slow or long-finned species are not well matched to a fast, competitive shoaler. Standard omnivore feeding with a variety of small granular, frozen and live foods keeps it in good health.
Conservation
Danio meghalayensis has not been formally assessed by the IUCN Red List; its status is Not Evaluated (NE). The species has a restricted known range — it is currently documented only from Meghalaya state, north-eastern India — and is described as very rare in the aquarium trade, suggesting limited captive representation and an uncertain wild population baseline.
Meghalaya's hill streams are subject to the same pressures affecting freshwater biodiversity across north-eastern India: deforestation on steep catchment slopes, sedimentation from land clearance, agricultural runoff and, increasingly, small-scale water extraction and damming. For a geographically restricted upland stream species with no formal IUCN assessment and a high reproductive rate (FishBase), the actual conservation position is unknown. It remains a priority candidate for field survey and formal evaluation.