The Phoenix Rasbora is a tiny Southeast Asian freshwater fish popular in nano aquariums because of its intense red coloration and peaceful schooling behavior.

Basic profile

• Scientific name: Boraras merah
• Common names: Phoenix Rasbora, Red Rasbora
• Family: Cyprinidae
• Origin: Indonesian Borneo, especially blackwater peat swamps
• Adult size: ~1.5–2 cm (0.6–0.8 in)
• Lifespan: typically 3–5 years in good conditions

Appearance

Phoenix Rasboras are extremely small and slim-bodied. Mature fish develop:

• bright orange-red to ruby coloration
• a dark lateral spot or stripe
• transparent to reddish fins

Males are usually slimmer and more intensely colored. Females are slightly rounder and paler.

Temperament

They are:

• peaceful
• shy
• schooling fish

Keep them in groups of at least 8–10, though 15+ is better. In small groups they often hide and lose color.

Good tankmates:

• other microfish
• small shrimp
• tiny peaceful bottom dwellers

Avoid:

• large or aggressive fish
• fast eaters that outcompete them

Aquarium setup

A Phoenix Rasbora does best in a heavily planted nano aquarium.

Recommended tank:

• Minimum: ~20 liters (5 gallons)
• Dense plants
• Dark substrate
• Driftwood and leaf litter
• Gentle flow
• Dim lighting preferred

They look especially striking in blackwater-style tanks.

Water parameters

They prefer soft, acidic water similar to their natural habitat:

• Temperature: 22–28°C
• pH: 4.5–7.0
• Soft water preferred
• Stable conditions are important

Frequent small water changes are better than large sudden ones.

Diet

They are micropredators and need very small foods.

Good foods:

• baby brine shrimp
• microworms
• daphnia
• finely crushed flakes
• micro pellets

Live and frozen foods improve coloration and breeding condition.

Breeding

Phoenix Rasboras are egg scatterers.

Typical breeding conditions:

• soft acidic water
• moss or fine plants
• dim lighting

Adults may eat eggs, so breeders often:

• remove parents after spawning
• or use a separate breeding tank

Eggs hatch in roughly 24–48 hours depending on temperature.

Common issues

Faded colors

Usually caused by:

• stress
• poor diet
• insufficient group size
• overly bright tanks

Sudden deaths

Often linked to:

• unstable water chemistry
• ammonia/nitrite spikes
• rough acclimation

Because they are tiny, they are more sensitive than many larger community fish.

Difference from Chili Rasbora

Phoenix Rasboras are often confused with Chili Rasbora.

General distinction:

• Chili Rasboras usually show a cleaner dark stripe and deeper red body
• Phoenix Rasboras often have a more orange-red tone with a flame-like pattern

Aquarium care for both species is very similar.