Phoenix Rasbora (Boraras merah) Breeding Guide

How to breed the Phoenix Rasbora (Boraras merah): a continuous egg-scatterer with no parental care that spawns into java moss in soft, acidic water.

Overview

Boraras merah is an egg-scattering, continuous spawner that exhibits zero parental care. In a well-established aquarium fry may appear naturally without intervention; a small dedicated container is used when higher numbers of fry are wanted.

Sexing

Mature females are noticeably rounder-bodied and often a little larger than males. Males display superior coloration, with dominant individuals showing the most intense hues.

Conditioning

Condition adults well, then introduce two to three well-conditioned pairs to the spawning container, transferring them slowly to minimise stress. If conditions are to their liking they should begin to spawn the following morning.

Breeding Setup

Use a small 10-15 litre container with minimal lighting and a bare substrate or mesh that lets eggs fall through but prevents adult access; plastic grass matting also works. Add a dense clump of java moss or fine-leaved plants filling about half the space, plus a small air-powered sponge filter. Spawning water is pH 5.0-6.5, hardness 1-5 °H, with temperature toward the upper end of the normal range (around 28 °C).

Spawning Behavior & Trigger

The species scatters its eggs continuously among the moss and plants. To prevent the adults from consuming the eggs, remove them after no more than two days in the spawning container.

Egg & Fry Care

Eggs hatch by day two, after which the fry survive on their yolk sacs for about 24 hours. They require microscopic foods such as Paramecium initially; after 7-10 days they accept Artemia (brine shrimp) nauplii and microworms. Delay water changes for one to two weeks to avoid shocking the young fish.

Common Challenges

As with other Boraras, the key difficulties are first foods small enough for the minute fry and avoiding losses from early water changes. Soft, acidic water and prompt removal of adults support a successful spawn.