Emerald dwarf rasbora

Danio erythromicron

Also known as Celestichthys erythromicron, Microrasbora erythromicron, Emerald Dwarf Danio

FreshwaterFish

Emerald dwarf rasbora (Danio erythromicron) — Cantospira · CC BY-SA 4.0

Care at a glance

Temperature: 68–75°F; 20–24°C
pH: 7.0–7.8
Adult size: 0.8 in; 2 cm
Minimum tank: 11 gal; 40 L

Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Egg scatterer · Medium
Rarity: Common
Family: Cyprinidae
Origin: Lake Inle basin, Shan State, Myanmar

Overview

The emerald dwarf rasbora is a tiny, peaceful schooling fish for a cool, densely planted tank. It is best with a little experience.

Did you know

The emerald dwarf rasbora lives only in the Lake Inle basin, which ties it strongly to one place for such a small fish. Its preference for cool, limestone-buffered water reflects that single high-elevation home. Most nano fish come from warm soft-water streams instead.

Caring for the emerald dwarf rasbora

Give emerald dwarf rasboras a tank of at least 11 gal (40 L), with dense planting, a dark substrate and dim light. Use gentle filtration from a sponge filter. Avoid driftwood or leaf litter, since tannin-stained acidic water does not suit them.

Hold the temperature at 68 to 75°F (20 to 24°C), and never let it climb above about 25 to 26°C. That makes them a poor fit for warm tropical communities. Keep the pH at 7.0 to 7.8.

Keep them in a group of at least 8 to 10. A group of 20 or more brings out their best color and confidence, and spreads out mild sparring between males. They are peaceful, timid fish of the middle water, so house them only with other small, calm species and no boisterous tank mates. Do not keep them with the closely related celestial pearl danio, also called the galaxy rasbora, since the two can hybridize.

Emerald dwarf rasboras scatter their eggs and give no parental care. They spawn readily in a mature planted tank, but the adults eat the eggs. A separate spawning setup raises the yield, and breeding is of medium difficulty.

Good to know

The emerald dwarf rasbora, Danio erythromicron, is a tiny cyprinid in the family Cyprinidae. It has also been classified as Celestichthys erythromicron and Microrasbora erythromicron over the years. It also goes by emerald dwarf danio.

In the wild

Emerald dwarf rasboras come from Lake Inle, a shallow, high-elevation lake in Shan State, Myanmar. The lake sits on limestone, so its water is clear, neutral to slightly alkaline, and cooler than most tropical setups.

Weekly picks

Tank mates

The emerald dwarf rasbora is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does an emerald dwarf rasbora need?

An emerald dwarf rasbora needs at least 11 gal (40 L). It spends most of its time in the middle.

What temperature and pH does an emerald dwarf rasbora need?

An emerald dwarf rasbora is comfortable at 68–75°F (20–24°C) with a pH of 7.0–7.8.

How big does an emerald dwarf rasbora get?

An adult emerald dwarf rasbora reaches about 0.8 in (2 cm).

Does an emerald dwarf rasbora need a group?

Yes. An emerald dwarf rasbora is a schooling species and should be kept in a group, not singly.

How does an emerald dwarf rasbora breed?

Emerald dwarf rasboras scatter their eggs and give no parental care. They spawn readily in a mature planted tank, but adults eat the eggs, so a separate spawning setup raises the yield.