Emerald Dwarf Rasbora Care Guide - Setup, Diet & Breeding

The Emerald Dwarf Rasbora is a tiny, striking danio with a deep blue-green body crossed by several narrow dark vertical bars. Depending on the light, its scales can flash emerald, turquoise and metallic blue, while the fins often show warm reddish or orange tones, particularly in mature males.

This species is active but generally peaceful, spending much of its time in the middle and upper areas of the aquarium. It is a social fish that displays its best colours and most natural behaviour when kept in a properly sized group, with males making brief displays and pursuing one another without causing serious harm.

In the wild, Emerald Dwarf Rasboras come from the Lake Inle region, a highland freshwater system known for extensive aquatic vegetation and distinctive endemic fish. Their compact body and bold patterning are adaptations well suited to moving through plant growth and open shallows.

Although it was once placed in the genus Microrasbora, the species is now generally classified as Danio erythromicron. Its small adult size and vivid appearance have made it a popular choice for planted nano aquariums, though its delicate proportions mean it is best appreciated with other peaceful, appropriately sized fish.

Emerald Dwarf Rasboras are native to Lake Inle and nearby waters in Shan State, Myanmar, in Southeast Asia. They inhabit shallow freshwater environments associated with aquatic vegetation and rocky or open lake margins.

A group should be kept in an aquarium of at least 40 litres, with a footprint of roughly 60 by 30 cm or larger to provide useful swimming length. Use a mature, stable setup with open areas, gentle water movement, fine dark substrate, smooth stones, driftwood and dense live plants around the edges. Floating plants and mosses provide security and spawning cover, while subdued lighting helps the fish show their strongest colours.

Up to 3 cm (1.2 inches) in total length; females are usually the larger sex, while males generally reach about 2.5 cm (1 inch).

Offer a varied diet of tiny, high-quality foods, including finely crushed flakes, micro pellets, frozen cyclops, daphnia, baby brine shrimp and other suitably sized live foods. Small live and frozen foods help maintain their colour and condition, while several modest feedings are preferable to one large meal because of their small mouths.

Emerald Dwarf Rasboras can share an aquarium with other peaceful small fish such as celestial pearl danios, chilli rasboras, pygmy corydoras, small Otocinclus and other gentle nano species. They are also suitable with peaceful freshwater shrimp, although newly hatched shrimplets may be eaten. Avoid large or boisterous fish, fin-nippers, aggressive species and fast-feeding tankmates that may outcompete them for food.

Emerald Dwarf Rasboras are egg-scattering spawners that can breed among fine-leaved plants, mosses or spawning mops. Condition a group with varied small live and frozen foods, then provide dense cover where eggs can be deposited. Adults may eat the eggs, so remove the spawning material or separate the eggs after spawning. The eggs usually hatch within a few days, and the tiny fry should initially receive infusoria or another appropriately sized first food before progressing to newly hatched brine shrimp.

Females are typically larger, deeper-bodied and less intensely coloured than males. Males are slimmer and often display brighter blue-green body markings and more noticeable red or orange in the fins, especially when courting.