Dwarf Neon Rainbowfish (Melanotaenia praecox)

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The Neon Rainbowfish, known scientifically as Melanotaenia praecox, is a small, brilliantly colored freshwater fish native to Indonesia’s Mamberamo River.

Admired for its iridescent blue body and red or yellow fins, this species is a favorite in tropical aquariums for its active swimming behavior and compatibility with other peaceful fish.

Ideal for community aquariums, the Neon Rainbowfish is a hardy and vibrant species, adding a splash of color and energy to any aquatic environment.

So, let’s dive in and discover the wonders of this enchanting species.

Quick Facts

Species SummaryScientifically classified as Melanotaenia praecox. Hardy and adaptable, suitable for beginners and experienced fishkeepers.
AppearanceStreamlined body with a slightly arched back.
Size: 2 to 3 inches.
Color: Vibrant blue with a yellow to orange color.
Males have red fins and tails, females have yellow fins and tails
Lifespan5 to 7 years in captivity with proper care.
Behavior & TemperamentPeaceful and friendly. Schooling fish, best in groups of 6-8. Active swimmers, prefer middle and upper tank levels.
DietOmnivorous diet: flake/pellet food, brine shrimp, daphnia, bloodworms.
Tank RequirementsMinimum tank size: 20 gallons.
Water parameters: Temperature 72°F – 80°F, pH 7.0 – 8.0, Hardness 5 – 15 dGH.
Tank MatesCompatible with peaceful community fish like Corydoras Catfish, Dwarf Gouramis, Betta Fish, etc.
BreedingQuite easy – Separate breeding tank with higher temperature and live plants.

Species Summary

The Neon Rainbowfish is a stunning species of fish.

These fish are native to freshwater habitats in Australia, particularly in rivers and streams.

They are scientifically classified as Melanotaenia praecox.

These fish are incredibly hardy and adaptable, making them a popular choice for both beginner and experienced fishkeepers.


Neon Rainbowfish have a streamlined body with a slightly arched back.

They have a pointed snout and a large mouth.

These fish have a vibrant blue body with a yellow to orange stripe that runs horizontally along their sides.

The upper body is typically darker compared to the lower half.

The dorsal fin is tall and triangular, while the anal fin is long and narrow.

Males are more colorful than females, with red fins and tails.

Females, on the other hand, tend to be slightly larger and have yellow tails and fins.

The average size when fully grown is around 2 to 3 inches in length.


With proper care, Neon Rainbowfish can live for 5 to 7 years in captivity.

Female dwarf neon rainbowfish swimming an an aquarium
Female Neon Rainbowfish

Behavior & Temperament

Neon Rainbowfish have a peaceful temperament and are generally friendly towards other fish in the aquarium.

They are schooling fish, which means they thrive when kept in groups of at least 6 to 8 individuals.

Keeping them in smaller numbers or alone can cause stress and affect their overall well-being.

Neon Rainbowfish are active swimmers, and they prefer to occupy the middle and upper levels of the tank.

They enjoy exploring their surroundings and appreciate the presence of plants and hiding spots.


Caring involves providing them with suitable tank conditions, a balanced diet, and a peaceful community tank environment.

To ensure the well-being of these fish, it is recommended to maintain a minimum tank size of 20 gallons.

This size allows for sufficient swimming space and accommodates a small school of Neon Rainbowfish.

Tank Size

A minimum tank size of 20 gallons is recommended for a school of Neon Rainbowfish.

This size provides enough room for them to swim and explore their environment comfortably.

Additionally, a larger tank allows for better water stability and reduces the risk of potential aggression among tank mates.

Water Parameters

Neon Rainbowfish require a well-maintained and stable aquatic environment to thrive.

The following table outlines the ideal water parameters:

Water ParameterIdeal Range
Temperature72°F – 80°F (22°C – 27°C)
pH Level7.0 – 8.0
Water Hardness5 – 15 dGH

Maintaining these water parameters will help ensure the overall health and well-being of your Neon Rainbowfish.

What To Put Inside Their Tank

In order to recreate their natural habitat, it is important to provide Neon Rainbowfish with a well-decorated aquarium.

These fish are native to freshwater rivers and streams in Australia, where they are found among aquatic plants and driftwood.

  1. Plants: Include live or artificial plants to provide coverage and mimic their natural habitat. They appreciate plants with broad leaves, such as Java Fern or Anubias.
  2. Substrate: Use a fine-grained substrate, such as sand or gravel, to create a natural-looking bottom. This substrate will also provide a suitable environment for beneficial bacteria.
  3. Decor: Add driftwood, rocks, and caves to create hiding spots and create a visually appealing environment. These elements also provide opportunities for shy fish to retreat.
  4. Water Flow: Neon Rainbowfish prefer a moderate water flow. Adding a filter can help create the ideal water circulation.

Food & Diet

Neon Rainbowfish are omnivorous and have a varied diet in the wild.

In captivity, they can be fed a combination of flake or pellet food, supplemented with live or frozen foods.

A well-balanced diet may include high-quality flakes or pellets, brine shrimp, daphnia, and bloodworms.

It is important to feed them small portions multiple times a day to ensure they receive adequate nutrition.

Tank Mates

Neon Rainbowfish are compatible with a wide range of peaceful community fish.

Here are some suitable tank mates:

  • Corydoras Catfish
  • Dwarf Gouramis
  • Betta Fish
  • Harlequin Rasboras
  • Cherry Barbs
  • Swordtails
  • Guppies
  • Otocinclus Catfish
  • Zebra Danios
  • Ember Tetras


Neon Rainbowfish breed easily.

To encourage breeding, provide a separate breeding tank that is well-decorated with live plants and spawning mops.

The water temperature should be slightly higher, around 80°F (27°C), and regular water changes are beneficial.

The female will lay her eggs in a sticky adhesive that attaches to plants or spawning mops, where they will hatch in about a week.

Once the fry has hatched, they can be fed crushed flakes or specialized fry food until they are large enough to eat regular food.

Why You Should Consider This Fish

Neon Rainbowfish are a colorful and captivating addition to any aquarium.

Their vibrant colors and peaceful nature make them a popular choice among fishkeepers.

They are relatively hardy and adaptable, making them suitable for both beginners and experienced aquarists.

Their active swimming behavior and compatibility with a variety of tank mates add life and vibrancy to any community tank.


How big do neon rainbowfish grow?

Neon Rainbowfish typically grow to a size of around 2 to 3 inches in length.

Are neon rainbowfish compatible with other fish?

Yes, Neon Rainbowfish are compatible with a wide range of peaceful community fish. It is important to consider the temperament, size, and water requirements of potential tank mates.

What is the lifespan of a neon rainbowfish?

With proper care, Neon Rainbowfish can live for 5 to 7 years in captivity.

Can neon rainbowfish be kept in small aquariums?

It is recommended to provide Neon Rainbowfish with a minimum tank size of 20 gallons to ensure their well-being and allow for proper swimming space.

Do neon rainbowfish require a heater in their tank?

Neon Rainbowfish thrive in a water temperature range of 72°F – 80°F (22°C – 27°C). Therefore, it is recommended to use a heater to maintain a stable and suitable temperature in their tank.

Photo of author


Irma Bense is the founder of BetterFishkeeping.com. She has over 42 years of experience in keeping fish.She has kept both freshwater and saltwater fish through the years.She has extensive knowledge in breeding numerous species of fish from Show Guppies, Cory Catfish, German Blue Rams to Apistogrammas.You can learn more about Irma on the 'About' page.

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