Skip to Content

Boesemani Rainbowfish: Care Guide (Diet, Tank & More)

get 5 secrets to thriving plants

Boesemani rainbow fish are a colorful addition to any freshwater tank.

They are a popular choice amongst freshwater aquarium enthusiasts because of their colorations, peaceful demeanors, and ease of care. 

While they are easy to care for, it is important to learn everything you can about them to make sure they are thriving. Read on to learn all you need to know and more about the Boesemani rainbowfish!

Rainbowfish Care Sheet

Scientific NameMelanotaenia boesemani
Common NameBoesemani Rainbowfish, Boeseman’s Rainbowfish, Rainbowfish, Melanotaenia Boesemani
SizeUp to 4.5 inches
Minimum Tank Size30 Gallons

Boesemani rainbowfish are peaceful freshwater community fish that are dual-toned. They typically have warm tones of color on their back half with cool tones on their front half, hence the rainbowfish name. They grow up to 4 inches and have a peaceful demeanor. They need at least a 30-gallon tank. 

Appearance & Temperament


Their appearance is how they received the rainbow name, as well as one of the reasons they are very popular amongst aquarists.

These bright fish are dual-toned as their rear half is one color and their head another. 

Their back half is made of warm tones such as yellows, oranges, and reds. While the head is the exact opposite with cool tones of purples, greens, and blues.

Boeseman's rainbowfish (Melanotaenia boesemani)

The middle of their bodies is where the two hues blend with each other and can result in thin black or green stripes.

The fish can control the intensity of their color, reflecting mood, health, illness, stress, or that they are ready for mating.

Their environment and interactions with other fish can also affect how they change their color. Their most vibrant hues will start to show when they grow around 2.5 inches.

Boesemani rainbow fish have flat oval shaped bodies, with the tail fin poking out at the end. Besides their tail fin, the other fins are fairly small and do not extend much past their body. 

Their heads narrow at the point at the front and because of this, they have smaller mouths and larger eyes. 

While their eyes may pop out a bit, this does not take away from the fact that they are stunning fish. 

With both spectrums of the rainbow (cool and warm colors) included in their colorations, they are quite the show-stopper.

Temperament and Behaviors

Boesemani rainbow fish are very peaceful freshwater aquarium fish. They tend to stay in the middle levels of the water and are pretty active if they are healthy.

They will move rapidly as they swim around open spaces.

They are very social amongst their own kind and other species as well. They are shoaling fish and larger groups keep them happier.

Watching as they shoal swim around the waters highlights their behaviors and colors as they move in unison with each other.

Size and Lifespan

The average lifespan for Boesemani rainbowfish is around five to eight years in the wild. Meanwhile, in captivity, they can live long lives away from predators, some even living up to 12 years.

Typically the Boesemani rainbowfish will grow up to 4 inches when they are fully grown.

This means they are on the smaller end of the spectrum when it comes to freshwater aquarium fish, but not as small as tetras or guppies.  

Gender Differences

The two main things to look at when sexing the Boesemani rainbow fish are their color and size.

The male is much larger than the females, as an adult male can be up to 4.5 inches and the females typically only grow to about 3 inches.

Besides having larger bodies, the males also have deeper bodies than the females and are more vibrant in their colors.

Females are still the same beautiful colors, just duller in color along with having an intense color with it. The female fins will look more yellow or opaque.

Also, gender differences can easily be spotted during spawning periods. The female will become more round as she fills with eggs. At the same time, the males will become even brighter to attract a mate.

What to Feed Rainbow Fish: Diet and Feeding

Boesemani rainbow fish are omnivores and need a well-balanced diet, however, they have limitations for the diet due to their smaller mouths.

In the wild, they will eat anything they come across. They will eat small plant matter and tiny insect larvae.

Dried food such as flakes or pellets is a good foundation for some of the nutrients that they need. However, live and frozen foods will provide most of the needed nutrients.

This is because as dried foods are prepared they lose many nutrients during manufacturing.

Providing a well-balanced diet with live foods and vegetables will bring out their colors even more. Live or frozen foods such as daphnia or mosquito larvae are excellent options. 

Although they eat vegetation, they typically will not eat the live plants in their tank only eating what breaks away from the plants.

Providing them with small pieces of zucchini or spinach are great additions to their diet.

To avoid overfeeding, they should be fed only what they can consume fully in a couple of minutes.

Always remember to remove any uneaten food from the bottom of the tank after feeding time is done. This will help keep the tank cleaner for them.

Boesemani rainbow fish should be fed twice a day, this will help prevent their digestive system from being overworked.

Boesemani Rainbowfish Tank Mates

Boesemani Rainbow fish are a very peaceful species and will do well in a community tank.

However their size may scare much smaller fish, this should be considered when picking tank mates. Ideally similar-sized or smaller tank mates are more suitable than nano fish for example.

Boesemani rainbowfish should be kept in groups of at least 6 of their own kind. This should be the first tank mates as less than a group of 6 has negative effects.

They can be shy and need to be in groups as they do not fare well by themselves. When this happens they will keep to themselves and their colors can dull. 

Ideal tank mates for Boesemani Rainbowfish:

  • Danios
  • Larger Tetras
  • Rasboras
  • Other Rainbowfish

They also do well with nonfish tank mates because even though they have larger bodies they have small mouths. Meaning they will not try to eat the invertebrates in the tank, great choices are assassin snails or ghost shrimps.

Aquarium Setup & Tank Requirements

The minimum tank size for the Boesemani rainbowfish is 30 gallons. This size of a tank can comfortably keep a group, or shoal, or six fish. Any smaller than this and they can become stressed from feeling overcrowded.

Due to their size and the fact that they are active fish, they need plenty of room in the tank to thrive. After the initial 6 in the 30-gallon tank, an extra five gallons need to be added for each additional fish.

With that being said, an even larger tank is preferred if you are planning to add live plants, other species of fish, and decorations to the tank. 

Because the Boesemani rainbowfish is endemic to one area, their natural habitat needs to be replicated in the tank in order for them to thrive. The water parameters need to be ideal for this fish.

Water Parameters:

  • Water Temperature:  Between 75℉ to  86℉
  •  pH Levels: 7.0-8.0
  • Water Hardness: 8 -25 dGH

Since the Boesemani rainbowfish stays in middle to upper levels of the tank, choices in the substrate are wider.

With that being said, sands, rocks,  and pebbles are great options for a substrate. A standard aquarium light is also suitable for them.

A high-quality filter system is optimal for maintaining excellent water quality which is very important for Boesemani rainbow fish. 

Their natural habitat has dense vegetation, your tank will need to be heavily planted to mimic this.

The plants not only provide them with safety, but this is where they will lay eggs if you plan to breed. Ensure you do not overplant your tank as these fish needs plenty of room to swim around in.

Breeding Boesemani Rainbowfish

As long as optimal conditions are provided during the process, breeding Boesemani rainbowfish is fairly easy to do.

Although breeding is fairly easy to do, the hard part is raising the fry. In order to have successful breeding the following water conditions are needed in a separate breeding tank:

  • Water Temperature: around 82
  • pH Level: around 7.5
  • Water Hardness:9-19 dGH

It is also very important to condition the adult fish prior to breeding. To condition the rainbow fish for breeding, they will need to be fed higher quality food than normal.

This should include live and plant foods. Live food can include several worm types or even baby brine shrimp.

In the breeding tank, there should be plenty of vegetation. Densely growing plants such as java moss or water sprite are ideal.

Around these plants is where the female will lay and scatter her eggs in the tank. The spawning period for them lasts about two weeks, with the female laying around 10 to 20 eggs per day.

Females will start rounding out with eggs as she becomes ready to mate. During this time, the male begins to show off his mating strip on his forehead.

The male will fertilize the female’s eggs near planted areas and they will be scattered as they are laid.

The Boesemani rainbowfish do not have parental instincts and will likely try to eat the eggs after they are scattered.

Because of this, after the eggs are scattered on the plants, you should remove them and replace them with fresh plants for the next day. Moving the eggs to a safe environment will protect them from being eaten. 

The tank the eggs are moved to should have the same water conditions as the breeding tank. This allows the eggs to fully develop and hatch.

The eggs will hatch after about 7 to 12 days, and for the first week, they should be fed infusoria or liquid foods.

After a week, the fry can be fed something larger, like brine shrimp nauplii, until they are large enough for the adult’s diet.

The young fry tends to stay near the surface of the water, meaning you will want to avoid sinking foods.

Since they stay at the top level of the tank, you will want to make sure they can’t get sucked up by your filter.

There are sponged you can purchase to combat this issue.

Their diet and water conditions need to be kept up with until they grow more and are able to live in the community tank.

Typically, the “growing” phase can last at least 2 months. Boesemani rainbow fry can be quite the process as they grow very slowly, so patience is key.

Natural Habitat and Distribution

Boesemani rainbowfish are native to the tropical waters of Indonesia. They can only be found in the shallows of the Ayamaru Lakes.

This is the only natural population of the Boesemani rainbowfish. Due to their popularity, they are heavily bred in captivity.

These lakes are perfect as they have a warm climate. Boesemani rainbow fish stay in shallow waters to avoid large predators. These areas are densely vegetated providing them with more protection and security.

The waters in the lakes are slow-moving, have plenty of light, and are alkaline and hard. These conditions are perfect for the rainbowfish and why it is the only natural population.

These conditions are key to having them stay happy and healthy in captivity.

get 5 secrets to thriving plants