Green fire tetra - Aphyocharax rathbuni

Scientific name: Aphyocharax rathbuni

Common name: Green fire tetra

Family: Characidae

Usual size in fish tanks: 4 - 5 cm (1.57 - 1.97 inch)

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Recommended pH range: 6 - 7.5

Recommended water hardness: 8 - 20°N (142.86 - 357.14ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 20 - 26 °C (68 - 78.8°F)

The way how these fish reproduce: Spawning

Where the species comes from: South America

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Middle levels

Short description

The Green fire tetra (Aphyocharax rathbuni) is a small, active schooling fish native to the Rio Paraguay basin in South America. It shows a glowing greenish body sheen with a red tail base, making it a striking yet underrated community fish. As with most tetras, keep them in groups of 6 or more to reduce stress and display natural behavior. They appreciate subdued lighting, open swimming areas, and patches of plants or driftwood for cover. Hardy and adaptable, they tolerate a range of water conditions but thrive best in slightly acidic, soft to moderately hard water.

Origin

Native to the Rio Paraguay basin in Brazil and Paraguay. They are typically found in calm tributaries and floodplain habitats with vegetation and leaf litter.

Food and feeding

An omnivorous micro-predator. Provide a high-quality flake or micro-pellet as a staple, supplemented with frozen or live foods such as brine shrimp, daphnia, and bloodworms. They feed midwater and readily take small sinking or drifting foods.

Sexing

Males are slimmer and show distinct white tips on the dorsal and anal fins. Females are fuller-bodied, especially when gravid.

Breeding

A typical egg scatterer. Use a dimly lit spawning tank with fine-leaved plants or spawning mops. Condition adults on live foods, and spawning usually occurs at daybreak. Eggs hatch in 2–3 days, with fry free-swimming in 5–6 days. Start fry on infusoria or other microscopic foods, then transition to newly hatched brine shrimp.

Lifespan

Expected lifespan is 3–6 years, with well-kept individuals occasionally living up to 7 years.

Behavior & compatibility

Generally peaceful, making them ideal for community tanks. Keep with similarly sized, calm species such as other tetras, rasboras, dwarf corydoras, and small peaceful cichlids. Males may spar occasionally, but serious aggression is rare in properly sized groups. Avoid mixing with very slow or long-finned tank mates to prevent fin-nipping.

Tank requirements

Tank size: at least 60 liters for a school; larger tanks allow more natural behavior.
Aquascape: open swimming space with planted edges, driftwood, and leaf litter for cover.
Lighting: subdued or filtered through floating plants.
Filtration: gentle to moderate flow with good oxygenation.

🐟 Schooling tip:

Green fire tetras (Aphyocharax rathbuni) are schooling fish and should never be kept alone or in pairs. A group of at least 6–8 individuals is essential for their health and natural behavior. Larger groups reduce stress, bring out brighter colors, and minimize fin-nipping or skittish behavior.