Species NameMelanotaeniidae (family that includes several species)
Common NameRainbowfish
Care LevelModerate
Lifespan5-8 years
Adult Size2-6 inches (depending on species)
Minimum Tank Size30 gallons
Temperature72°F – 78°F (22°C – 26°C)
Water ConditionspH 6.5-8, medium to hard

About the Rainbowfish – Species Summary

Rainbowfish, belonging to the Melanotaeniidae family, are captivating freshwater fish native to the lakes, rivers, and swamps of Papua New Guinea, Indonesia, and Australia. Their name is aptly derived from the myriad of vibrant colors they exhibit, reminiscent of a rainbow. They are known not only for their beauty but also for their active and peaceful nature. Coming in various sizes and color patterns depending on the species, Rainbowfish have become a sought-after choice for many aquarists.

Rainbowfish Lifespan

With the right care, Rainbowfish can thrive in an aquarium setting for 5 to 8 years. Their lifespan can be influenced by factors such as water quality, diet, and overall tank conditions. Like any fish, providing them with a stable environment, a balanced diet, and routine care will promote a long, healthy life.


The Rainbowfish’s beauty is undeniable. Their bodies shimmer with iridescent scales that radiate hues of blue, orange, yellow, green, and red. The intensity of their coloration often depends on their mood, age, diet, and overall health. Some species also exhibit unique patterns and fin shapes, adding to their allure.

Average Size

Rainbowfish vary in size depending on the species. Most commonly kept species in home aquariums range from 2 to 6 inches in adult length. Before choosing a specific species, it’s essential to know its potential size to ensure they have ample space to swim and grow.

Rainbowfish Care

Tank Size

For most Rainbowfish species, a 30-gallon tank serves as a starting point. However, given their active nature, bigger is always better. If keeping them in a school, which is often recommended, ensuring ample space is essential for their well-being.

How To Set Up Their Tank

Replicating their natural habitat will ensure Rainbowfish feel at home. Opt for a fine gravel or sandy substrate. Incorporate live plants like Java fern or Anubias, which not only enhance the tank’s aesthetics but also offer hiding and resting spots. Driftwood and rocks can also be added to provide structure and mimic their native environment.

Lighting Requirements

Rainbowfish are diurnal, meaning they are active during the day, so they appreciate well-lit tanks. Good lighting can also accentuate their vibrant colors. However, a balance should be struck to avoid excessive light, which can promote unwanted algae growth. Using a timer to regulate the light cycle can help.


A pH level ranging from 6.5 to 8 suits Rainbowfish. It’s crucial to maintain consistent pH levels to avoid undue stress and potential health complications.


Rainbowfish thrive in temperatures between 72°F and 78°F (22°C – 26°C). Maintaining a stable temperature is essential, so investing in a reliable heater and thermometer is a wise decision.

Water Parameters

Medium to hard water is preferable for Rainbowfish. Regular water changes and routine testing to ensure low ammonia, nitrite, and nitrate levels will go a long way in keeping your Rainbowfish healthy.

Disease Potential

Like all aquarium fish, Rainbowfish are susceptible to various diseases, including Ich, fin rot, and fungal infections. Ensuring good water quality, quarantining new fish, and promptly treating any signs of illness can mitigate these risks.

Food & Diet

Being omnivores, Rainbowfish have a varied diet. They readily accept high-quality flake food, but their diet should be supplemented with live or frozen foods like brine shrimp, daphnia, and bloodworms. This diverse diet not only meets their nutritional needs but also enhances their vibrant colors.

Behavior and Temperament

Rainbowfish are peaceful, active swimmers, often seen in the middle or upper regions of the tank. They are best kept in schools of six or more, which allows them to exhibit their natural behaviors and reduces stress.

Tank Mates

Due to their peaceful disposition, Rainbowfish can cohabit with a range of tank mates. Ideal companions include similarly sized and temperamented fish like tetras, danios, and certain types of barbs. Avoid keeping them with aggressive or overly large fish that might see them as prey.


Breeding Rainbowfish in a home aquarium is achievable with some preparation. They are egg scatterers, often laying their eggs among fine-leaved plants. Providing a separate breeding tank with dense planting or spawning mops, and maintaining optimal water parameters, can encourage breeding. Once the fry hatch, they should be fed with infusoria or commercially available fry food until they are large enough to accept standard food.

Remember, Rainbowfish are a gem in the world of freshwater fish. Their active nature combined with their radiant appearance ensures they remain a popular choice for aquarists of all levels. With proper care, they can be a delightful addition to any aquarium.

Rainbowfish FAQs (Frequently Asked Questions)