Green Neon Rasbora Breeding Guide

How to breed Microdevario kubotai, a tiny egg-scattering nano cyprinid that provides no parental care, so adults must be removed; eggs hatch in about 72 hours.

Overview

Microdevario kubotai is a tiny cyprinid reaching only about 1.9 cm in standard length, native to rivers and streams of Peninsular Thailand and the Ataran basin in Myanmar. It is a free-spawning egg-scatterer of advanced breeding difficulty that gives no parental care, so adults will consume their own eggs and fry if left in place.

Sexing

Mature females tend to be deeper-bodied and noticeably larger than the more compact, intensely coloured males.

Conditioning

Well-established fish can be conditioned together in a mature planted tank on a varied diet of small foods, keeping water values within the species range of 22-27 °C and pH 6.0-7.5. Because the species is a shoaling fish that does best in a large group, conditioning a sizeable shoal increases the chance that several adults come into spawning condition at once.

Breeding Setup

For controlled breeding, use a separate container filled with aged water and densely furnished with fine wool mops, Taxiphyllum (java moss) or other fine-leaved plants among which the eggs can fall. Filtration and lighting are optional, though a small air-powered sponge filter may be added. The dense planting both stimulates spawning and shields the falling eggs from the parents until the spawners are removed.

Spawning Behavior & Trigger

Introduce a single pair or a small group of males and females to the spawning container. These egg-scatterers deposit eggs randomly among the vegetation without parental care, so the adults should be removed after two to three days to prevent predation of eggs and fry. In a mature, healthy planted aquarium spontaneous spawning may also occur, with a limited number of fry surviving without intervention.

Egg & Fry Care

Eggs incubate for approximately 72 hours, temperature-dependent, and the fry become free-swimming three to four days after hatching. Begin feeding with 5-50 micron grade foods, advancing to Artemia nauplii and microworm once the fry are large enough to accept them.

Common Challenges

The principal challenge is the extremely small size of the fry, which require correspondingly tiny first foods and clean, stable water. Because the adults readily predate eggs and fry, prompt removal of the spawners is essential to obtain a worthwhile yield.