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The Phoenix Rasbora

The Phoenix Rasbora

Posted by Max Gandara on on 4th May 2025

Phoenix Rasbora (Boraras merah): A Fiery Gem for Nano Aquariums

If you’re a fan of vibrant, tiny fish that thrive in peaceful, planted environments, look no further than the Phoenix Rasbora (Boraras merah). With its striking red coloration, peaceful demeanor, and active schooling behavior, this micro fish is a favorite among nano tank enthusiasts and aquascapers alike.

Often mistaken for its close cousin the Chili Rasbora (Boraras brigittae), the Phoenix Rasbora stands out with a slightly different body pattern and color distribution — making it a unique choice for collectors and aquarists aiming for variety in their small setups.

Origins and Natural Habitat

The Phoenix Rasbora is native to southern Borneo, particularly in Indonesia, where it inhabits blackwater streams and peat swamps rich in tannins. These waters are typically:

  • Soft and acidic

  • Low in minerals

  • Shaded by dense jungle canopy

  • Filled with leaf litter and detritus

Replicating these conditions in your aquarium can help bring out the best in their coloration and behavior.

Appearance

True to its name, the Phoenix Rasbora blazes with a fiery red-orange hue, especially when kept in ideal conditions and a healthy group.

Key Features:

  • Size: 0.6–0.8 inches (1.5–2 cm)

  • Body color: Transparent red-orange with scattered dark speckles or a faint lateral stripe

  • Eyes: Bright, reflective, giving them a curious and lively expression

  • Sexual dimorphism: Males are more intensely colored; females are slightly rounder with duller tones

Under dim or blackwater-style lighting, their color intensifies beautifully.

Tank Setup and Requirements

Because of their size and natural environment, Phoenix Rasboras are ideal for nano tanks, but they still benefit from thoughtful aquascaping and excellent water quality.

Ideal Tank Conditions:

  • Tank Size: 5 gallons minimum (10+ recommended for a proper school)

  • Temperature: 72°F to 80°F (22°C to 27°C)

  • pH: 5.5 to 7.0

  • Hardness: Very soft to moderately soft

  • Aquascape: Dense plants, leaf litter, driftwood, and subdued lighting

  • Filtration: Gentle sponge filter or low-flow filter

Keep them in groups of at least 8 to 10 to reduce stress and encourage their natural schooling behavior. The more you have, the better they look and behave.

Behavior and Tankmates

Phoenix Rasboras are peaceful, shy, and social. They’re ideal for community nano tanks but do best with other similarly sized and gentle species.

Compatible Tankmates:

  • Chili Rasboras (closely related)

  • Celestial Pearl Danios

  • Pygmy Corydoras

  • Otocinclus catfish

  • Dwarf shrimp (e.g., Amano, Neocaridina)

  • Sparkling Gouramis

Avoid keeping them with larger or fast-moving fish, which may outcompete them for food or intimidate them.

Feeding

These micro rasboras are micropredators, feeding on tiny insects and zooplankton in the wild. In captivity, they prefer small, high-quality foods.

Best Foods:

  • Live or frozen baby brine shrimp

  • Microworms, daphnia, vinegar eels

  • Crushed flake food

  • Micro pellets

  • Powdered nano fish foods

Feed in small quantities 1–2 times daily. Their small mouths and timid nature mean they may take time to adjust to prepared foods.

Breeding

Phoenix Rasboras are egg scatterers, and while breeding in a community tank is possible, a separate breeding setup increases success.

Breeding Tips:

  • Use soft, acidic water and live plants (like Java moss)

  • Provide dim lighting and leaf litter

  • Condition adults with live foods

  • Adults will spawn in plants or fine-leaved structures

  • Remove adults post-spawning; they may eat eggs

Fry are tiny and require infusoria or commercial liquid fry food until they’re large enough for baby brine shrimp.

Why Choose Phoenix Rasboras?

  • Perfect for nano and aquascaped tanks

  • Peaceful and easy to care for

  • Stunning color in groups and under proper lighting

  • Low bioload and compatible with shrimp

  • Fun to watch in schools

Final Thoughts

The Phoenix Rasbora may be small in size, but it delivers big in visual appeal and personality. Ideal for nano tanks and planted aquariums, these little flames are both elegant and low-maintenance when kept in the right conditions. With a gentle touch and proper environment, you’ll be rewarded with a lively display of color, movement, and harmony.