Dwarf Emerald Rasbora

Celestichthys erythromicron

Also known as: Emerald dwarf rasbora, Microrasbora erythromicron, Danio erythromicron

Water Parameters

• Temperature: 21–26°C
• pH: 7–8
• Hardness (GH): 143–268 ppm (8–15 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A jewel of a nano fish from the highland Lake Inle in Myanmar: a stocky little rasbora barely 2cm long, the males banded with emerald-green bars over a rosy body and marked with a dark spot at the tail. Closely related to and often kept with the celestial pearl danio, it shares that fish's quiet charm and its preference for a mature, densely planted tank, but differs in one useful respect: coming from a hard, alkaline lake, it is comfortable in the harder water many Australian keepers have on tap. It is a slightly shy, group-loving fish that needs numbers and cover to be seen at its confident best, displaying and sparring among the plants. Peaceful, shrimp-safe, and undemanding once established, it is an excellent and slightly unusual centrepiece for a hard-water nano community.

Tankmates

A peaceful micro-fish closely related to the celestial pearl danio and an ideal companion for it, sharing the same need for a mature, planted nano tank and a group of at least eight. Males are more vividly striped and display to one another with fins spread, sparring harmlessly to establish a loose hierarchy, which is best spread across a larger group with plenty of cover. Genuinely shrimp-safe thanks to a tiny mouth, and far too small to threaten any fish, but equally vulnerable to being eaten, so it belongs only with other nano species. Unusually for a small rasbora it comes from the hard, alkaline water of Myanmar's Lake Inle, so it suits harder Australian tap water better than most of its nano relatives.

Compatible with

• Celestial Pearl Danio
• Chili Rasbora
• Ember Tetra
• Pygmy Corydoras
• Cherry Shrimp
• Otocinclus

Avoid keeping with

• Betta
• Angelfish
• Large Cichlids
• Fin Nippers
• Any Larger Fish

Common Problems

• shyness in groups smaller than 8
• difficulty taking large foods (needs small particle sizes)
• stress in new or unstable tanks
• predation by any larger tankmate

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20