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Rainbowfish Overview, Care Guide, Breeding Tips & More

The rainbowfish is a recent addition to fish keeping as a hobby but has garnered mainstream appeal due to its unique appearance, low requirements, and relative ease of breeding.

Due to their docile nature, they make excellent tank mates. Some species prefer to school within their species and may hang out with other rainbowfish.

Species Overview

Level of CareEasy to Medium
TemperamentMostly peaceful
AppearanceVaried colors ranging from red, yellow, silver, black, and blue
Life Expectancy5 to 8 years in a home aquarium
Size2.4 inches to 8 inches
DietOmnivorous and need both meat-based and vegetable-based foods
FamilyMelanotaeniidae and Bedotiidae
Tank Size10 gallons to 50 gallons depending on the species
Tank EnvironmentProvide tall plants and other structures for rainbowfish to visit
Tank MatesExtremely peaceful and get along well with other species

They originate from the freshwaters of eastern and northern Australia, Southeast Asia, and certain regions of New Guinea. All their species are unique and have micro variations that differ depending on the lake or stream they live in. Irrespective of the fish selected, They get along well with other community species such as Discus and Tetras.

More than 61 species have been discovered so far, with more unique sub-species being uncovered daily. It is worth noting that it comprises two main subspecies. The Bedotiidae and Melanotaeniidae families include more significant, more active fish like the Red, the Turquoise and the Madagascar Rainbowfish (the Threadfin Rainbow is a slight exception to this rule).

The second group contains Telmatherinidae and Pseudomugilidae families.

The Telmatherinidae family includes the Celebes Rainbowfish and the Marosatherina ladies.

The Pseudomugilidae comprises smaller, less active fish known as “Blue Eyes” for their unique appearance.

Most of these species are named after their appearance, which is brilliant and rather unique – even for freshwater fish.

It is worth noting that human activity, such as overfishing, has disrupted the natural habitat of some species. Life for some of these species can be very difficult in the wildlife.



They have bright, often iridescent colorations that uniquely respond to variations in different lighting conditions.

Common rainbowfish species have blue, silvery-green bodies with pink-colored bellies and red-orange or transparent fins. They use their elegant fins for swimming and getting around the tank.

Gender Differences

These are sexually dimorphic, which means that males and females have various appearances.

For instance, male Boseman’s Rainbowfish have deep red colors that strongly contrast female Boseman’s Rainbowfish with largely opaque bodies.

Females also tend to have a wide longitudinal band with a series of dark lines that often changes depending on their mood.

Another distinction between the two is that males have pointy dorsal fins while females are more rounded in appearance.


They have two dorsal fins and one anal fin. The anal fin allows them to swim at extremely high speeds in a short period.

In general, they have a laterally compressed body that resembles that often resembles an elongated diamond shape. This shape will vary from specie to specie, ranging from slender to a very deep-bodied appearance.

Despite having a narrow mouth, most rainbowfish species have a massive appetite and will devour a lot of food in a short period. As time passes, their backs will develop a slight bulge that can use to estimate their age.


Most species are relatively small, with the largest of them barely reaching a maximum size of 10 inches in span.

Species like the dwarf neon rainbowfish only reach a maximum size of 1” while others may reach a maximum length of 6”.

Celebes rainbow male looking at camera
Male Celebes Rainbowfish

Behavior & Temperament

Fishkeepers prize forktail rainbowfish because of their peaceful demeanor and excellent appearance. They are shoaling fish, which means they prefer to hang out in groups of 6 to 12.

It is not unheard of for rainbowfish from one species to hang out with rainbowfish from other species. A good rule of thumb is to select similarly sized tank mates that are peaceful and docile.

Forktail rainbowfish are mostly compatible with other rainbowfish, especially the dwarf neon rainbowfish and ornate rainbowfish. You can also place them in the same tank with tetras, barbs, gouramis, swordtails, loaches, and guppies.

Despite their docile demeanor, they will view smaller freshwater species as prey. It is true in the case of vampire shrimps, bamboo shrimps, and ghost shrimps. It won’t take long for the much larger rainbowfish species to start nibbling at them. They do have a voracious appetite, after all.


They’re a hardy species with a long lifespan of about 5 to 10 years if you take good care of them.

Tank Setup

As with other fish species, your goal should be to emulate their natural habitat effectively. It is doubly true for these fish since they require well-planted tanks.

Choose plants that can tolerate the hard, alkaline water that rainbowfish usually prefer. The tank should have dense vegetation with a sandy substrate and some bogwood to mimic their native habitat.

As a general rule, you will need a minimum tank volume of about 30 gallons. They can be very active swimmers, and some species are known to reach a length of about 10 inches. If you plan on keeping several rainbowfish, go for a tank size of about 60 gallons. The bigger, the merrier. Make sure also to provide two hours of natural sunlight to the tank.

If this isn’t possible, you can create some artificial lighting to mimic natural sunlight. Ideally, it should be done when you can view the aquarium because the lights will make them appear even more stunning.

Rainbowfish are known to jump out of their tanks now and then. It is why you should keep the tank covered adequately with a lid.

  • The temperature should be about 70 to 80° Fahrenheit.
  • Water hardness should never exceed 25dGH.
  • The substrate should be a mix of sand and gravel.
  • The pH value of the water should be 6.5 to 8.0.
  • The water movement should be moderate, not too fast and not too slow. Just enough to keep the fish simulated.
  • The tank should be about ten times the length of an adult.
  • Keep the tank in a quiet location because it is easy to startle them

They mostly occupy the middle of the tank and don’t swim to the top or bottom very often. Keep this in mind when selecting tank mates. Choose tank mates that don’t prefer the middle area of the tank.

If your aquarium contains different species, make sure to provide plenty of spots to hide in should they get harassed.

Include plenty of plants and logs where they can hide from aggressors. It’s easy for them to get stressed out to the point of sickness, with the worst-case scenario being death.

Tank Mates

These are mostly schooling fish that thrive in a particular environment. They are non-aggressive and do exceptionally well in a large community aquarium of similarly sized fish.

You can mix them with other docile and shy-natured fish for good results. They prefer a 1:1 ratio of males to females to keep the peace between them. Otherwise, the males will continuously pick on females which will increase their stress levels.

Here’s how you should keep them:

  • 6 Rainbow: 3 females and three males
  • 7 Rainbow: 4 females and three males
  • 8 Rainbow: 5 females and three males
  • 9 Rainbow: 5 females and four males
  • 10 Rainbow: 6 females and four males

Notice a pattern? The females should almost always outnumber males to keep the peace between them.

Group of red rainbowfish
Group of Red Rainbowfish

Food & Diet

All types are omnivorous creatures that thrive on a mixed diet comprising plants and animals. They are not very picky when it comes to food, so this part should be easy for beginners. That being said, it is vital to provide them with balanced and varied nutrition.

They will thrive on Betta Treat, Spirulina Flakes, and Color Flakes, as well as a combination of live and frozen foods. They will also readily eat vegetable-based pellets and, if possible, mosquito larvae. Mosquito larvae are illegal to culture in many areas.

Experienced aquarists claim that a diet of live foods improves the coloration of the males and improves their mood.

Breeding Guidelines

Breeding them is relatively easy, but it is recommended to keep a special breeding tank. This tank should contain a spawning mop or plants with delicate leaves, such as java moss.

Install a sponge filter in the tank. It should contain plenty of plant-based and live foods. Your goal with the breeding tank is to emulate ‘floods’ as they occur in their natural habitat. During this time, they have access to higher quality food compared to the rest of the year.

You will have to choose a couple for this tank. Select the healthiest, most colorful fish from your main Aquarium to hatch healthy fry.

As a general rule, the male should have bright, vivid colors, and the female should be a bit chubby.

Rainbowfish are long-term spawners, which means they will lay their eggs over a long time. They will deposit their eggs every day in one cycle.

To speed up breeding, keep the water at a pH of around 7.5 (which is slightly alkaline), slightly hard, and at a temperature of about 80° Fahrenheit. You can initiate spawning faster by increasing the water’s temperature.

During this time, should feed the couple a steady diet of frozen and live food for at least a week.

Reproduction begins when they swim together after the male performs a small ‘ritual’ to attract females. A single courting session can take several cycles to complete. The female will lay her eggs every day, joined together by a tiny thread attached to the rocks or plants (such as java moss and water sprite) in the tank.

The eggs will take about 12 days to hatch after they are laid out. The fry may take very long to grow and be extra vulnerable to getting eaten; their most significant threat could be their parents. So take them out once they’re hatched.

Caution: While they are not known to crossbreed with other species, this can be a problem in the Aquarium, particularly in the Melanotaeniidae family.

These species tend to interbreed and create undesirable results. The fry belonging to mismatched parents will lose their coloration. Try to keep the bloodlines of rainbows distinct. Otherwise, their fry could lose those beautiful colors.

Juvenile turquoise rainbowfish
Juvenile Turquoise Rainbowfish

Hatching The Eggs

Once the eggs have been fully hatched, remove the parents from the Aquarium because they tend to eat their fry. Parents provide no parental care to their eggs and fry, so it’s best to separate them. The fry will take about ten days to hatch.

To increase the survival rate, Best to incubate the eggs. It would help if you mimicked the ideal circumstances to hatch the eggs. Rainbow fry will not survive in poor water conditions, so ensure the water is adequately conditioned before the fry emerges. Make sure to monitor the water levels regularly.

Try to keep the temperature around the eggs consistent by covering them with a foam box.

You may try to oxygenate the eggs by placing an air stone next to them. The air stone will make bubbles that will flow around the eggs.

After the fry emerges from their eggs, they should feed them on a diet of infusoria or liquid fry food until they are old enough to hunt small live food. It can be particularly challenging to raise fry because they take about two months to grow big enough. The water has to be clean during this entire process.

Please do not move to their parents’ tank until they’re old enough to defend themselves. Other fish, including their parents, will easily mistake them for food.

You can tell that the fry has matured once they’re big enough to eat crushed flakes, micro worms, and brine shrimp.

With a good diet (and lots of patience), your fry will grow into very healthy and bright-colored rainbowfish. It could take anywhere from 12 months to 24 months, depending on the species.

Common Diseases

Most of them are incredibly hardy, but they are vulnerable to diseases if their water is not maintained correctly. If the aquarium conditions are not at the proper levels, rainbowfish may be prone to columnaris.

It is indicated by tall hair-like strings that will hang off the sides and mouths. To clear up the issue, you’ll have to fix the problems with the tank’s water, and that should sort out the problem. If kept in an improper environment are too weak to survive infection or its treatment.

Two common diseases are White Spot Disease (also known as Ich), caused by a parasite known as Ichthyophthirius multifiliis and Velvet caused by Oodnium. Treating these infections can take a significant toll on your fish.

Other fish, plants, substrate, plants, and even decorations can harbor bacteria that could make their way into your fish’s body and infect them. It is why it is essential to clean the tank regularly. Quarantine live species before introducing them into the tank so as not to disrupt the water’s balance.

The great thing about fish is that you can contain an infection outbreak if you catch it early. Although some sensitive species of rainbowfish are prone to get infected well before the first warning signs can be spotted. The best way to prevent disease is to mimic the fish’s natural habitat.

It will lower the stress the fish will have, making them happy and healthier. When fish are stressed out, they are more likely to acquire all kinds of diseases.

Where to Buy?

It is effortless to buy rainbow fish for sale from online stores, online forums, Craigslist, and your local pet store. They only cost about $3 to $4, depending on the rarity of the species. Expect to pay more for rarer species.

Frequently Asked Questions

Do rainbowfish live in the Ocean?

No. Most species of rainbowfish can’t survive in the ocean because the water is too salty for them. The salt in the water will cause the water to flow out of their cells, thus, killing them. These can be primarily found in freshwater bodies like rivers, streams, swamps, and lakes.

Can you keep rainbowfish with angelfish?

Yes, you can keep rainbowfish and angelfish together in the same tank because they thrive in similar aquarium conditions. They are also similar in size, which reduces the chance that they will feel intimidated or compete for territory.

Wrapping Up

If you are looking to add a splash of color to your Aquarium, then the rainbowfish is the ideal species for you. It is readily available online and doesn’t require much in the way of maintenance.

Their natural habitat is easy to mimic, so you won’t break an arm and a leg to accommodate their water conditions. When fry first hatches out of their eggs, they will have a rather plain appearance, but they will grow into gorgeous adults given enough time.