Devario assamensis

Overview

Deep-bodied Devario assamensis is an energetic schooling fish that favors cool water. Prolonged tropical warmth is unsuitable, making summer cooling and oxygenation especially relevant. Mirik red, redline, and blood stripe have all been used as trade labels.

Distribution & habitat

The type locality lies near Tangla in Assam. Records also involve West Bengal's Mahananda and lower Brahmaputra tributaries, some rising in Bhutan, plus Assam's Kalmoni drainage and the vicinity of Mirik. Mirik collections probably came from surrounding streams rather than the artificial lake.

If these records represent the same species, elevation ranges from about 250 m to 1,767 m, potentially higher in Bhutan. Clear, oxygenated streams with gravel and rocks are the likely habitat, with seasonal changes in water volume and turbidity.

Aquarium setup

Sand, fine gravel, rounded stones, and roots can form a stream-style layout. Hardy attached plants are useful additions. Maintain clean stable water, high oxygen availability, and moderate rather than violent flow.

Change about 30–50% weekly and fit the lid securely. Keep within the established cool-water range, adding aeration in summer if required. Extreme air temperatures from the region are not long-term aquarium water targets.

Diet & feeding

Insects and their larvae are strongly suspected natural prey, while broad acceptance is expected in captivity. Quality dry food can be supplemented regularly with small live or frozen bloodworms, water fleas, and Artemia.

Behaviour & compatibility

It is not normally aggressive, but continual movement and rapid feeding can disturb slow or timid fishes. Choose robust companions of similar size that also suit cooler water.

At least eight to ten individuals help reduce nervousness and distribute hierarchy-related interactions. Males often display stronger color among rivals. Provide enough open swimming room for the group.

Sexual dimorphism

Mature females are expected to be somewhat larger, rounder in the abdomen, and less colorful. Maturity should be considered when interpreting these differences.

Breeding

The genus's general egg-scattering, nonparental method provides a possible approach rather than a fully verified protocol for this species. Occasional young may appear in a mature planted aquarium. For greater survival, a separate dim spawning aquarium can protect eggs with mesh, synthetic grass, glass marbles, fine plants, or mops.

Use mature slightly acidic to neutral water toward the upper end of the appropriate temperature range, with gentle air-driven circulation. Introduce one or two well-conditioned pairs when females are ripe. Ready fish commonly spawn within a day, after which females look slimmer. Remove adults after about two days even if spawning was not witnessed.

In the general method, hatching commonly takes 24–36 hours, followed by free swimming several days later. Start with Paramecium or comparable tiny foods, progressing to Artemia nauplii, microworms, and powdered preparations when large enough.

Notes

A deep body and central stripe reaching the tail fork are useful clues, but similar large forms from Assam still raise identification problems. Trade references to red lines cannot establish species identity by themselves.