Celestichthys Erythromicron

Datasheet

General Description

The Celestichthys erythromicron, also known as Microrasbora erythromicron or Danio erythromicron, was formerly classified as part of the Microrasbora genus but is now considered a danionin. This fish, marketed under various names like 'emerald dwarf danio' or 'thick band purple zebra danio,' is a small adult species with a significantly reduced size, typically less than 20 mm SL, due to miniaturization. It prefers still or slow-moving waters, often in nutrient-poor habitats such as forest peat swamps, and is found in Lake Inle in Myanmar.

Aquarium Setup

The Celestichthys erythromicron thrives in a heavily planted aquarium with a dark substrate, broken lines of sight, and gentle filtration. Floating plants are beneficial, but it is advised to avoid driftwood and certain leaf litter types that release tannins. Water conditions should be maintained with a hardness of 215-357 ppm, pH of 7.0-8.0, and a temperature range of 20-24°C. For specific tank setup details, refer to the accompanying table.

Behaviour

This species tends to be timid and may face intimidation or food competition from larger or more boisterous tankmates. It shows shoaling behavior rather than schooling, with rival males engaging in regular sparring during daylight hours. While nipped fins within the group are common, this aggression typically does not extend to tankmates. To reduce shyness, providing companions like Celestichthys choprae or Microdevario species can be beneficial.

Feeding and Diet

In the wild, Celestichthys erythromicron feeds on small invertebrates, algae, and zooplankton. In captivity, a varied diet including small live and frozen foods like Daphnia and Artemia is recommended for optimal coloration and breeding condition. New specimens are advised to be acclimatized with small live foods initially before introducing dry and frozen options once they are settled.

Reproduction & Dimorphism

The species is an egg-scattering spawner without parental care. A controlled breeding setup with fine-leaved plants or wool mops can increase fry yield. Males are more colorful with iridescent blue vertical bars, while females tend to be slightly larger and rounder, especially when gravid. Spawning typically results in around 30 eggs, and young fry become free-swimming after approximately 3-4 days.

Habitat and Distribution

Celestichthys erythromicron is native to Lake Inle and its surrounding watershed in Myanmar, with clear, shallow water containing dense submerged macrophytes. The lake's unique ecosystem and karstic nature provide a habitat for various endemic species, including the celestial fish. Fisheries within the lake region are characterized by neutral to slightly alkaline water conditions and seasonal fluctuations in connectivity due to water flow dynamics.