Phoenix rasbora

Overview

The phoenix rasbora (Boraras merah) is one of the smallest fish in the hobby, a micro-rasbora barely 2 cm long, flushed with red and marked with dark spots. Peaceful, delicate and a little shy, it is a jewel for the planted nano tank, where a good-sized shoal drifting through soft, tinted water glows like embers. It rewards patience and a mature, stable setup.

Tank & water

A shoal is happy in a planted nano of 30 litres (8 gallons) or more. Key requirements:

• Temperature: they like it warm, 24–28 °C, held steady with a small heater.
• Soft, acidic water: target pH 4.0–7.0 and low hardness; botanicals and driftwood that tint the water suit them perfectly.
• Gentle filtration: such tiny fish need soft flow — a sponge filter is ideal and won’t draw them in.
• Planting and shade: dense plants and dim light give security and deepen their red.

Feeding

Phoenix rasboras are micro-omnivores with minuscule mouths. Feed finely crushed flake or micro-pellet plus small live and frozen foods — baby brine shrimp, cyclops, daphnia, microworms — which they take best of all. Feed small amounts once or twice a day. A mature, planted tank also supplies microfauna they graze between meals.

Tankmates

Only the smallest, gentlest tankmates are safe: chili rasboras, ember tetras, pygmy corydoras, otocinclus and dwarf shrimp. Avoid anything large enough to eat or bully them. Keep a shoal of at least eight so they feel secure — see best nano fish for a small tank for more pairings.

Common mistakes to avoid

• Adding them to a new, unstable tank
• Keeping too few, which leaves them shy and pale
• Hard, alkaline water (they need soft and acidic)
• Larger tankmates that eat or outcompete them

Give phoenix rasboras a mature, soft, planted nano and a proper shoal, and this ember-red micro-fish becomes a living highlight of the tank.