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Encyclopedia / Tetras / Rainbow tetra
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Variations

1 kinds · tap one for a closer look

Rainbow tetra

Nematobrycon lacortei · Rainbow emperor tetra, Lacorte's tetra, Lacortei

Peaceful; keep six or more.

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3.6 cmBody length, without tail ✓
22–28 °CTemperature ✓
5–7.2pH ✓
108 LSmallest tank ✓
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Tank mates
Check your own mix →
Not recommended
  • Tinfoil barb eats animals up to about 5 cm. Rainbow tetra only grows to 3.6 cm.
Not recommended
  • White cloud mountain minnow needs cool water and makes a lot of waste, while Rainbow tetra is tropical.
  • Only a narrow temperature range suits both: exactly 22 °C.
Not recommended
  • Giant gourami eats animals up to about 10 cm. Rainbow tetra only grows to 3.6 cm.
With conditions
  • Only a narrow pH range suits both: 7–7.2.
With conditions
  • Only a narrow pH range suits both: 7–7.2.
Compatible
Compatible
Compatible
Compatible
Compatible

321 species in our list are a good match.

Facts checked against sources on 16 Oct 2026. ✓ means a source backs it; ? means no reliable source yet. See sources

Care and water

Hardness ✓1–10 dGH
Group size ✓8 or more
Temperament ✓Peaceful
Swims at ?Middle
Care level ✓Easy
Diet Omnivore
Lifespan ?Unknown
Size in shops 2.5–3.5 cm
Growth Medium

Behavior

Peaceful; keep six or more.

Food

Flakes and small foods.

Tap a food to see what it is.

Male or female

Adult males have red eyes, longer dorsal, anal and tail fins, and more colour. Females have blue-green eyes and look fuller-bodied, especially when carrying eggs.

Health

Common problems. Tap one to see the signs. This is a guide, not a diagnosis.

Breeding

Egg-scatterer · Moderate

Bred like the emperor tetra: condition males and females apart, then move a single pair in the evening to a small, very dim tank with fine-leaved plants, spawning mops or mesh, soft acidic water (pH 5.0-7.0, GH 1-8) at 24-26.5°C. Eggs are laid in small batches over several hours; remove the adults afterwards.

Pairing

Keep a group of 8-10 and move a well-conditioned trio or group to a spawning tank.

Setup

30-40 L tank with a spawning grid or dense java moss, soft to medium water (pH 6-7.5), a sponge filter and subdued light.

What starts it

Heavy live-food conditioning, then a water change with slightly cooler water in the morning.

Eggs

Eggs hatch in 24-36 hours and the fry are free-swimming 4-5 days later. No sourced egg count found.

Raising the fry

Start with infusoria or powdered fry food, then newly hatched brine shrimp; sort by size as they grow.

Common mistakes
  • Leaving adults with the eggs
  • Poor conditioning of the parents
  • Overfeeding the fry tank
Full breeding guide, day-by-day plan and simulator →

Where it lives in the wild

RegionSouth America – western Colombia
Rivers and lakesRío San Juan basin on the Pacific slope
HabitatSlow forest streams
Native rangeAbout 150 km across
See it on the world map

The story of the rainbow tetra

The emperor tetra's only congener, from forest pools in the Río San Juan system of western Colombia. Weitzman and Fink described it in 1971 and named it after the American aquarist Rosario LaCorte. The two Nematobrycon species are almost identical in build but very different in colour.

Stanley Weitzman and William Fink described this tetra in 1971, naming it after aquarist Rosario LaCorte. It is a close relative of the emperor tetra. Males have bright red eyes and a three-pointed tail.

First described by Stanley H. Weitzman & William L. Fink in 1971. Named for Named after American aquarist Rosario LaCorte.

  • Males have red eyes, while females' eyes are greenish.
  • Its tail ends in three points.
  • It is a close relative of the emperor tetra.

Sources

15 facts checked with sources