Taxonomy & naming
Danio feegradei was described by the Indian ichthyologist Sunder Lal Hora in 1937, based on specimens collected from roadside drains at Sandoway (Thandwe), Rakhine State, in lower Myanmar. The holotype is deposited at the Zoological Survey of India (ZSI F. 12477/1). Hora originally placed the fish in the genus Brachydanio, then widely used for the smaller, slender danios; the combination Brachydanio feegradei appeared throughout the twentieth-century literature. The Catalog of Fishes (Eschmeyer, CAS) — the authority for valid names — now subsumes Brachydanio within Danio, so the current valid binomial is Danio feegradei Hora, 1937.
The species belongs to the "true danios" assemblage within Danio — small, horizontally patterned shoaling cyprinids of South and Southeast Asia — and sits within the narrow set of species restricted to the Rakhine coastal drainages, geographically separated from the better-known Irrawaddy and Salween fauna. No subspecies are recognised.
Morphology
The Yoma danio is a small, elongate, laterally compressed cyprinid reaching approximately 2.5 in standard length — large for a "small" danio, putting it at the upper end of the genus by aquarium-size standards. The body profile is typical of the true danios: a streamlined torpedo shape, slightly upturned mouth suited to surface and mid-water feeding, and the pair of fine rostral barbels characteristic of Danio.
The colour pattern has not been described in detail in the available literature for this article, but the species is a member of the horizontally banded danio group; the genus is characterised by dark-and-light stripes running from behind the operculum to the caudal base, often extending onto the fins. Sexual dimorphism follows the usual danio pattern — females become noticeably deeper-bodied and more rounded when gravid, while males remain slimmer and more torpedo-shaped.
Habitat
Danio feegradei is endemic to small coastal streams and roadside drains on the western slope of the Rakhine Yoma (Arakan Range) in western Myanmar. Its known range extends from the Thade River drainage south to the area north of Kyeintali — a narrow coastal strip of watersheds draining directly to the Bay of Bengal rather than into the Irrawaddy. This geographic isolation, bounded by the Rakhine hills to the east and the ocean to the west, makes it one of the more restricted-range danios in Myanmar.
The habitat is monsoon-influenced forest stream country: small, often seasonally variable watercourses that swell and warm during the wet season and retreat to cleaner, cooler, well-oxygenated pools and riffles in the dry. Water conditions are soft to moderately hard (reported GH 5–15; hardness 36–215 ppm across the range) and slightly acidic to neutral (pH 6.5–7.5), with temperatures of 64–77 °F — cooler than many tropical species, reflecting the hilly, forested catchment and seasonal variation.
Feeding
In the wild, Danio feegradei is an opportunistic insectivore and micropredator, preying on insects and their aquatic larvae taken from the surface and water column of the small forest streams it inhabits. This diet is typical of the genus: danios are visually oriented, fast-moving surface-to-midwater feeders that exploit whatever invertebrate prey the current delivers or that falls from overhanging vegetation.
In the aquarium the species adapts readily to prepared foods — good-quality dried flakes and small pellets form a sound base — and responds well to regular offerings of live or frozen invertebrates such as daphnia, bloodworm, and mosquito larvae, which maintain colour and breeding condition. Feeding should be varied and offered in small amounts several times a day to keep pace with its active metabolism.
Mating
Like all members of the genus, Danio feegradei is an egg-scattering, non-guarding spawner. There is no nest, no pair bond, and no parental care of any kind. In nature, spawning is almost certainly triggered by the onset of the monsoon — the rise in water temperature, increase in flow, and flooding of marginal vegetation that seasonally signal reproductive readiness across the danio group.
Courtship follows the typical danio pattern: a driving male pursues a gravid female through vegetation or over the substrate, flanking her closely until eggs and milt are released together in a brief, energetic embrace. The adhesive or weakly adhesive eggs fall into fine-leaved plants, moss or gravel, after which both parents take no further interest — and will consume the eggs if given the opportunity.
Breeding
Danio feegradei breeds in the aquarium in the same manner as other egg-scattering danios. A separate, mature, densely planted spawning tank is the usual approach — fine-leaved plants (java moss, hornwort) or a layer of marbles over the base allows eggs to fall beyond the reach of the adults. Conditioning the group with live and frozen foods for a week or two prior to spawning improves yield.
A small temperature rise into the mid-range and the addition of fresh, slightly cooler water can initiate spawning at first light. Adults scatter adhesive eggs among the plants and must be removed promptly after spawning to prevent predation. Eggs hatch in roughly 48–72 hours depending on temperature; larvae become free-swimming a few days later and accept infusoria and paramecium initially, followed by newly hatched brine shrimp as they grow. There is no parental care at any stage.
In the aquarium
The Yoma danio is an active, peaceful shoaler best kept in groups of at least six — the typical danio minimum that allows the fish to school naturally and directs intra-group chasing away from tankmates. A longer aquarium of 47 in or more suits its swimming style, with a flowing, well-oxygenated setup reflecting its stream origins: rocks, smooth gravel, hardy plants such as Microsorum or Anubias at the sides, and open water in the centre for free movement.
Water conditions should be soft to moderately hard, slightly acidic to neutral (pH 6.5–7.5), and kept on the cooler side of tropical — 72–77 °F is the recommended range, and the species tolerates the lower end of that range comfortably. Strong filtration providing good water movement and surface agitation is beneficial. Because it is a restricted-range Myanmar endemic with limited availability, it is primarily a species for enthusiasts of unusual danios rather than a standard community fish.
Conservation
Danio feegradei has not been evaluated by the IUCN Red List and carries a status of Not Evaluated (NE). However, its biology and range raise legitimate conservation concerns: it is known only from a narrow strip of coastal streams on the western slope of the Rakhine Yoma in western Myanmar, a geographically isolated range that makes it inherently vulnerable to localised habitat loss.
The Rakhine coastal zone faces pressures from deforestation, agricultural conversion, road construction — its type locality is roadside drains, themselves a human-altered habitat — and the general degradation of small forest watercourses. A formal IUCN assessment would clarify whether population sizes and trends justify concern, but the combination of a small natural range, montane forest stream habitat, and the broader pressures facing Myanmar's freshwater biodiversity suggests this is a species worth monitoring.