Danio roseus · Rosy Danio

Overview

Hardy and peaceful, Danio roseus adapts readily to a planted community aquarium. Fish of mixed ancestry may occur in trade, so provenance matters when maintaining a clearly identified breeding line.

Distribution & habitat

It occurs in the Mekong basin of northern Thailand and Laos, with additional localities in northern Myanmar. Well-oxygenated forest streams are typical, but backwaters and a main-channel record show broader habitat use. Depth, flow, and chemistry vary seasonally, and some occupied streams are turbid.

Aquarium setup

Dark substrate and substantial planting show the fish well, provided open swimming length remains. A stream arrangement with smooth stones, gravel, wood, and attached plants is another option. Supply moderate circulation with sheltered areas and a tightly sealed cover.

Diet & feeding

Insects and larvae are considered likely wild foods. Aquarium feeding is usually easy: offer suitably sized quality dry food plus regular small live and frozen foods to support color and condition.

Behaviour & compatibility

A group of eight to ten or more promotes confidence and male displays. Select peaceful companions of compatible adult size, activity, and water requirements.

Sexual dimorphism

Females tend to be larger and deeper-bodied, particularly when carrying eggs.

Breeding

It scatters eggs and provides no care, so a mature planted tank may occasionally yield a few survivors. To raise more, condition adults and place one or two ready pairs in a dim spawning aquarium with mesh or fine plants protecting eggs. Small cooler-water additions and tiny live foods may encourage spawning the next morning; a slimmer female can indicate that eggs were released.

Separate adults afterward and protect young with established sponge filtration. Eggs commonly hatch in about 24–36 hours, with free swimming several days later. Begin with infusoria-sized food, later adding Artemia nauplii and microworms.

Notes

A slim body, relatively short rostral barbels, and absence of dark rear-body stripes help distinguish it from a close relative. Crosses have been produced, and suspected hybrid fish circulate in the hobby; powdery blue bodies and strongly red fins do not establish pure identity.