Emerald Dwarf Rasbora

Although its name includes "rasbora," the emerald dwarf rasbora is a danio and a close relative of the celestial pearl danio. The narrow vertical bars along its body, shimmering between blue-green and purple, are the species' most distinctive feature; in males the spaces between these bars are orange-pink and the fins orange-red. There is a dark spot on the caudal peduncle.

It grows to about 2.5 cm. It is a calm and somewhat timid species; it shows its colors in a densely planted, dim and quiet aquarium. It can be considered for both tropical and coldwater aquariums, since it struggles at high temperatures.

It is endemic to Inle Lake on Myanmar's Shan Plateau and the surrounding waters. The lake is shallow, clear and densely vegetated; the water is hard, alkaline and, because of the altitude, cooler than tropical lowland waters. The species lives hidden among these plants.

• Volume: at least 40 liters for a group of 8–12.
• Water: 20–24°C, pH 7–8, moderately hard to hard water. Soft, acidic water is not suitable in the long term.
• Plants: very dense planting, moss and floating plants; diffuse the light.
• Flow: gentle.
• Heat: in aquariums that rise above 26°C in summer, consider cooling or extra aeration.

Omnivorous, but its mouth is small. It accepts micro granules and fine flakes; supplement with newly hatched brine shrimp, frozen cyclops and daphnia. Newly arrived fish may at first take only live or frozen food.

Peaceful but timid. It moves in a loose group among the plants and in the lower to middle layers. Males display to each other by flaring their fins and engage in short chases; this behavior is natural and softens as the number of females increases.

Good companions: Neocaridina shrimp, celestial pearl danios, otocinclus, small and calm corydoras species, nerite snails.

Avoid: active and large species, fish that need warm water, any species with a mouth big enough to swallow it.

At least 8, ideally 12 or more individuals; a female-heavy group (1 male : 2 females) is the most balanced arrangement. Males constantly establish a hierarchy among themselves; if there are few females, the dominant male can wear out the others. Small groups are almost never seen.

It deposits its eggs among moss and fine-leaved plants; there is no parental care and the eggs are eaten. In an aquarium with dense moss, a small number of fry may grow up on their own. For controlled breeding, a small container filled with moss is used and the adults are removed after a few days. The fry are very small; start them on infusoria and microworms.

• Warm water: staying above 26°C for long periods shortens its lifespan.
• Starvation: feed new fish that refuse dry food with live and frozen food.
• Stress: in an open, unplanted aquarium it hides constantly.

Males are more colorful: their vertical bars are distinct, the body between them is orange-pink and the fins are orange-red. Females are paler, brownish olive and have a fuller belly; their bars look faint.