Information, Freshwater fish, Species

Rainbowfish: Complete Species & Care Overview

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by Jason Matthews



Rainbowfish is a type of freshwater fish popular for its unique and colorful appearance. Today, there are more than 50 types of rainbowfish originating from different regions like Australia, Indonesia, Madagascar, and New Guinea. This fish is typically easy to care for, active, and also friendly. 


Scientific NameBoesemani Rainbowfish (Melanotaenia boesemani)
Madagascan Rainbowfish (Bedotia geayi)
Threadfin Rainbowfish (Iriatherina werneri)
Red Rainbowfish (Glossolepis incisus)
Common NamesBoesemani Rainbowfish – Boesemani rainbowfish
Threadfin Rainbowfish – Featherfin rainbowfish
Red Rainbowfish – salmon-red rainbowfish, New Guinea rainbowfish
Life ExpectancyFive years
Adult Size4 – 5 inches (for most species)


Origin Australia, New Guinea, Indonesia, and Madagascar
Care LevelEasy
Temperament Friendly, social, and active
Diet Omnivorous
Tank LevelTop-dwellers or medium-dwellers
Water pH7 to 8 pH
Water TemperatureBetween 74° F and 78° F
Water Hardness9 dGH to 20 dGH
LightingSubdued and dim
Tank MatesTetras, Rasboras, Danios, Mollies

Fun Fact Corner

  • The body color of rainbowfish enhances with age. 
  • If you keep several male rainbowfish in a breeding tank, they’ll compete with each other by increasing their body color’s intensity!
  • Stress can cause your rainbowfish to lose its color.


Rainbowfish is mainly native to Australia, New Guinea, Indonesia, and Madagascar

There is no fixed place, as there are more than 50 varieties of Rainbowfish, each originating from a different region. Accordingly, the water requirements also vary. For instance, red rainbowfish originate from water bodies having high vegetation. On the other hand, Madagascan rainbowfish originate from clear streams. 

The table below denotes the places of origin of some popular rainbowfish species. 

Rainbowfish SpeciesOrigin 
Boesemani RainbowfishWest Papua, Indonesia
Axelrods RainbowfishSandaun Province, Papua New Guinea
Desert RainbowfishAustralia
Madagascan RainbowfishMadagascar
Banded RainbowfishNorth Australia
Threadfin RainbowfishNorth Australia, New Guinea
Neon RainbowfishMamberamo River Basin, Indonesia
Forktail RainbowfishPapua New Guinea
Redfin Dwarf RainbowfishAustralia, Papua New Guinea


Rainbowfish is one of the best fish for beginners. This fish species is friendly and social. Therefore, it will interact with most of the other tank mates. It is also extremely active and loves to swim fast against the current!

Note that rainbowfish thrive well in groups. So, it is best to keep a school of five to six rainbowfish together. If kept alone, it might become timid or feel stressed. 


The lifespan of rainbowfish varies as per the species. However, the average lifespan for most rainbowfish is five years in the wild. Certain species like Madagascan Rainbowfish can even live up to eleven years!

In captivity, a rainbowfish’s lifespan depends on the level of care you’re providing them. Hence, it can range anywhere between five and eight years

Size and Appearance

Most rainbowfish species can grow up to 4 to 5 inches in size. Again, the size varies as per the species. Certain species like neon rainbowfish can only grow up to 3 inches, whereas some like Van Heurn’s rainbowfish can even grow up to 7.9 inches. 

Body Shape and Color

Image: YAYImages, Depositphotos

No two rainbowfish species have the same body shape and color. They are all peculiar and offer unique colors and markings! 

The table below gives a general idea about the body shape and color of the most popular rainbowfish species. 

Rainbowfish SpeciesBody ShapeBody Color 
Boesemani RainbowfishFlat and ovalBicolored – blue tones near the head and orange tones near the tail. 
Madagascan RainbowfishStreamlined shapeSilver due to the presence of shiny scales. The fins and tail have a bit of yellow, along with black markings. 
Banded RainbowfishLong and deep body with a narrow head Comes in various body colors like red, green, blue, yellow, or purple. The fins are red. The presence of a black or blue mid-lateral strip is a standout feature.
Threadfin RainbowfishLong and sleek bodyConsidered the most attractive rainbowfish due to the presence of long and beautiful fins. 
The body consists of silver scales with tints of orange and blue. There are faint vertical stripes present on the body too. 
Neon RainbowfishOval and deep shapeThe body has a vivid and shiny blue color. The fins are red in males and yellow in females. 
Forktail RainbowfishTorpedo-shaped bodyThe body color is silver-gray, along with some greenish-yellow tints present all over. 
Red RainbowfishOval with rounded backsPresence of vibrant red and orange scales with tints of golden.

Differences Between Male and Female Rainbowfish

There are a few obvious differences between male and female rainbowfish. These differences typically differ species-to-species. However, some of the common variations are listed below. 

CategoryMale RainbowfishFemale Rainbowfish
Body ColorThey have a more vivid and striking body colorDull colors in comparison
FinsOften longer and more elongated Often more rounded
Other DifferencesPresence of a “courtship stripe” during spawning periodNo “courtship stripe” present


It is easy to breed most rainbowfish species. However, ensure that you breed two similar rainbowfish species, as cross-breeding may lead to stunted or underdeveloped fry. 

Follow the below-mentioned instructions to breed rainbowfish.

  1. Take a separate breeding tank, and add rainbowfish to it in a male-to-female ratio of 2:3
  1. Breeding requires higher temperatures. So, increase the water temperature to 77°F. Add some plants like java moss and spawning mops to the breeding tank.
  1. Allow the male and female to breed. You’ll notice that the males become more colorful (some might even possess a courtship stripe) while trying to mate with the female. 
  1. The female rainbowfish will become plumper during the spawning period. She’ll lay around 5 to 30 eggs in one go. 
  1. Once the female fish has laid the eggs, remove all adult rainbowfish from the breeding tank. Else, they might eat their own eggs.

You can feed infusoria to the free-swimming fry. Then, provide them with newly-hatched brine shrimp after a week!

Nutrition and Diet

Rainbowfish has an omnivorous diet. In the wild, this fish species feeds on insects, mosquito larvae, zooplankton, and tiny crustaceans. 

If you’re planning to keep rainbowfish in your aquarium, it is best to feed them high-quality pellets and flakes. You can also feed them live or frozen food options such as blood worms, daphnia, mosquito larvae, brine shrimp, and black worms.

You should feed rainbowfish three times a day, and ensure that they finish the food within three minutes. If you still notice some leftovers, reduce the amount next time.  

Tank Requirements

Most rainbowfish species are either top-dwellers or mid-dwellers. Note that as rainbowfish can be of various types, it is best to mimic the natural environment of the one you’re planning to keep in your aquarium. 

Tank Size

The tank size depends on your rainbowfish species. If your rainbowfish is around 3 inches, you can house six of them in a 15-gallon tank

On the other hand, rainbowfish species above 3 inches should be kept in a 30-gallon tank.

Water Requirements 

Most rainbowfish varieties prefer neutral and slightly-hard water. Yet, some varieties can also live in hard and alkaline water conditions.  

  • Water Temperature – Rainbowfish species belong to tropical or subtropical temperatures. So, try to maintain the water temperature between 74° F and 78° F.
  • Water pH – Neutral to alkaline water works best for most Rainbowfish species. Try to keep the water pH between 7 and 8.
  • Water Hardness – The water hardness should be kept between 9 dGH and 20 dGH.
  • Water Flow – Rainbowfish are quite active, and prefer moderate but gentle currents

Decoration and Plants 

Even though rainbowfish are pretty social and active, they need some hiding spots. So, keep a few rocks and caves in your aquarium. You can also keep a few popular aquatic plants.

Some of the best plants for rainbowfish include: 

  • Wisteria
  • Java moss
  • Java fern
  • Anubias
  • Hornwort
  • Crypts

When it comes to the substrate, opt for a dark and sandy substrate. This will bring out your fish’s color, while also mimicking its natural environment!


You should try to provide dim and subdued lighting to your rainbowfish. There should also be a few shaded areas in the tank. You can use floating plants to create shaded areas in your fish tank. 

Best Tank Mates

Rainbowfish can get along with most other fish species. You can even keep different rainbowfish species together in the same tank. Ensure that the male-to-female ratio is 2:3 to avoid any form of aggression.

Some other tank mates that are suitable to house with rainbowfish include: 

On the other hand, some fish species to avoid keeping with rainbowfish include:


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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