Devario xyrops · Blue Moon 'Danio'

Overview

Known before description as broken line, Devario xyrops is a schooling fish from the western Rakhine Yoma. Short anterior bars combine into a dark patch, followed by a broad horizontal stripe on the rear body.

Distribution & habitat

It is known from small streams and rivers draining the mountain range's western side north and south of Thandwe. Rakhine's main rainy season runs from May to October. Dry-season channels contract into linked pools; rains can deepen them by over a meter and greatly increase current.

At the dry-season type locality, a forest river formed pools about 2 m wide and no deeper than 1 m, containing clear colorless water with little or no flow. Another collection site was roughly 30 cm deep and 3 m wide, over gravel, pebbles, rocks, and leaves. Changes in agricultural use also affected the surrounding forest-edge landscape.

Aquarium setup

Rounded stones, sand, fine gravel, and roots make a suitable stream layout, with hardy attached ferns or Anubias. Seasonal floods and rapid water-level changes need not be reproduced in routine care.

Favor stable clean water, abundant oxygen, and moderate circulation while preventing organic waste buildup. Change approximately 30–50% weekly and fit the lid securely against jumping.

Diet & feeding

Insects and larvae are strongly suspected principal natural foods. Most aquarium offerings are accepted. Use quality dry food with regular small live or frozen bloodworms, water fleas, and Artemia.

Behaviour & compatibility

It is not notably aggressive, but continual movement and vigorous feeding can stress slow or timid companions. Similar-sized robust fish are better choices in spacious accommodation.

A group of at least eight to ten helps reduce nervousness and distribute social competition. Rival males often display stronger color. Numbers cannot substitute for adequate swimming room.

Sexual dimorphism

Mature females are expected to be larger, fuller-bellied, and less colorful. Consider maturity when interpreting these differences.

Breeding

The genus's general egg-scattering method offers a possible approach rather than a fully verified species-specific sequence. Small numbers of young may appear in mature planted aquariums. A separate dim breeding setup can improve survival using mesh, artificial grass, marbles, fine plants, or mops to keep adults away from eggs.

Use mature slightly acidic to neutral water at the warmer end of the suitable range, with gentle air-driven filtration or aeration. Add one or two well-conditioned pairs. Ready fish commonly spawn within a day, leaving females visibly slimmer; remove adults after about two days whether laying was seen or not.

Generic accounts give roughly 24–36 hours to hatching and several further days to free swimming. Begin with Paramecium or similar minute food, then introduce Artemia nauplii, microworms, and powdered dry foods as the young grow.

Notes

The anterior blotch comprises four or five partly merged bars that may form a solid patch, with a broad stripe behind it. The similar Devario anomalus is shallower-bodied and has more lateral-line scales: approximately 33–35 compared with 31–33 here. The central dark pattern alone cannot settle identification.