Boesemani Rainbowfish (Melanotaenia boesemani): Care Guide


Boesemani Rainbowfish (Melanotaenia boesemani), also known as Boseman’s Rainbowfish, is a species of freshwater fish that is a part of the Melanotaeniidae family. It is native to Asia – specifically the Ayamaru Lakes of West Papua, Indonesia where its numbers are currently dwindling.

Also known as the bi-color rainbowfish, the boesemani rainbowfish has two distinct colors, with its front colors ranging from bluish-silver to rich indigo, and its rear colors from yellow to bright orange. The intensity of its color, however, will vary based on sex, age, mood, and overall health. Another physical characteristic of this fish is its deep, laterally compressed body that is shaped like a flat oval.

Boesemani rainbowfish are boisterous, good-tempered fish and as their name suggests, they can bring vibrant color to any tank. These fish will most likely not have even reached their full color potential when found in most pet stores, but with proper care, their colors can become eye-catchingly vibrant over time.

Boesemani Rainbowfish Facts

  • Boesemani rainbowfish color intensity can change based on their mood; if they’ve just been chased around by a tankmate their colors may dull for a few moments before returning to normal.
  • During the mating process, male boesemani rainbowfish can intensify in color and develop a bright stripe on their head to attract the female rainbowfish.
  • Although boesemani rainbowfish are eggs scatterers, they don’t typically eat their eggs like other egg scatterers are known to do.
Boesemani Rainbowfish (Melanotaenia boesemani)
Boesemani Rainbowfish (Melanotaenia boesemani)

Boesemani Rainbowfish Care

Boesemani Rainbowfish are relatively hardy fish, although it’s still important to keep their water in clean condition. Maintaining the cleanliness of their tank will make it much easier to care for them in the long run. These agreeable fish are freshwater fish that thrive in clean environments and become at risk for diseases when their water quality declines.

Boesemani Rainbowfish Temperature

Boesemani rainbowfish enjoy warm tropical climates – their water should be kept between 75° and 86°, with 80° being a good midpoint temperature.

Boesemani Rainbowfish Water pH

Because boesemani rainbowfish fare well in hard, alkaline water, their water pH is best kept between 7 and 9.

Boesemani Rainbowfish Size

Boesemani rainbowfish can grow up to 4.5” in length, with their sizes varying based on age, sex, health condition. Boesemani rainbowfish are commonly sold at pet stores when they’re about 2” in size, but they’re able to grow much larger with proper care.

Boesemani Rainbowfish Tank Size

Boesemani rainbowfish require a minimum tank size of 30 gallons. Although, a tank that is closer to 50 gallons will provide maximum comfortability to these active fish. When deciding an appropriate tank size for boesemani rainbowfish, it’s a good idea to factor in whether their tank will be furnished– in which case their tank should be large enough for them to swim around plants, driftwood, and any other tank additions with ease.

Boesemani Rainbowfish Food & Diet

Boesemani rainbowfish are easy-to-feed omnivores and will accept most dried, frozen, and live foods. Feeding boesemani rainbowfish live food regularly will aid in maintaining their health and enhancing their vibrant colors. Brine shrimp, daphnia, and bloodworms are good choices of live food for these colorful fish and will ensure that they get a decent protein intake. If opting for flakes or pellets as their main dietary source, it’s important to select premium brands that contain high-quality ingredients and beneficial nutrients (e.g., beta-carotene) this will help boesemani rainbowfish maintain their vibrant colors. To provide them with a well-balanced diet, they will also benefit from plant-based food.

When feeding boesemani rainbowfish it’s important not to overfeed them, and instead, only feed them what they can eat within five minutes. Being sure not to overfeed these rainbowfish can prevent waste build-up, ammonia spikes, and lowered pH levels – all of which are hazardous to their health.

Boesemani Rainbowfish Lifespan

Boesemani rainbowfish have a relatively long lifespan and can live between 5 and 8 years when properly cared for.

Boesemani Rainbowfish Tank Setup

Boesemani Rainbowfish will appreciate live plants in their tank, as their native habitat has plenty of plants that provide them with a certain amount of security. Spindly plants are a good option for their tanks because they will be easier for the boesemani rainbowfish to swim through. When keeping in mind the kind of plants to include in their tank, the plants will need to be able to be strategically placed as not to interfere with their open swimming space.  

A substrate with rocks or sand will mimic the native habitat of the boesemani rainbowfish, although the tank’s floor is not very important because they will usually occupy the middle levels of the tank. Boesemani rainbowfish will prefer hard, alkaline water, and their water shouldn’t contain any traces of nitrates or ammonia. To maintain the cleanliness of their tank, one-third of their water should be replaced weekly, any excess algae should be wiped away, and their tank should have a decent filter. As for lighting, these fish will do fine with moderate to standard lighting.

Do Boesemani Rainbowfish like water flow?

Boesemani rainbowfish appreciate moderate currents and a good amount of water flow, so when choosing a filter for their tank, a power filter is a good option.

Boesemani Rainbowfish Breeding

When breeding boesemani rainbowfish, they should be transferred to a smaller breeding tank of about 20 gallons. During this process, it’s important to keep their water clean by making partial water replacements daily. It’s suggested to feed boesemani rainbowfish live food when attempting to breed them, as supplying them with a robust diet will help induce the mating process.

Boesemani rainbowfish typically scatter their eggs in fine-leaved plants, so it’s recommended to use java moss or a spawning mop during the spawning process. This spawning process will typically last for several days, during which the boesemani rainbowfish eggs will need to be collected daily and placed in a breeding box to hatch.

It’s strongly discouraged crossbreed boesemani rainbowfish with other species. Crossbreeding these rainbowfish would most likely produce fry that would not even grow to develop the brilliant colors that boesemani rainbowfish are known for.

Boesemani Rainbowfish Fry

Boesemani rainbowfish fry are tiny when they first hatch and remain close to the surface of the water. At this stage, they should be fed a diet of infusoria, plankton, or liquid fish food that is small enough for them to eat and will not sink in the tank. As they grow, they can slowly be introduced to baby brine shrimp as their main dietary source until they’re old enough to eat adult fish food.

During the boesemani rainbowfish fry growing stage, tank cleanliness is paramount. To keep their tank clean, a siphon can be used to remove any debris that has accumulated, and a sponge filter can be used to filter out the water.

Properly caring for boesemani rainbowfish fry is necessary to their development. It will usually take a year for them to reach adult size.

Boesemani Rainbowfish Male or Female

Male boesemani rainbowfish are vibrant in color and usually larger than their female counterparts which are smaller with a duller coloration.

How long does it take for Boesemani Rainbowfish eggs to hatch?

Boesemani rainbowfish eggs typically hatch in 7-12 days.  

When do juvenile Boesemani Rainbowfish start to get their colors?

While boesemani rainbowfish are usually sold at pet stores when they’re still around 2” long, their colors are not fully developed at that size. The colors of these ornamental fish don’t truly begin to show until they reach adult size (around 3”). It’s important to remember that their diet and water quality play a huge role in the development of their colors.

Boesemani Rainbowfish Tank Mates

Boesemani rainbowfish are very peaceful fish that are known for being good community fish. Although it’s recommended to keep boesemani rainbowfish in schools of six or more, because of their peaceful nature, they will typically get along well with various other species.

What is the best male to female ratio for Boesemani Rainbowfish?

The male to female ratio for boesemani rainbowfish should approximately be 3:2, which would mean three female fish for every two male fish. Keeping a good ratio of female to male fish is necessary to ensure that they all live in harmony.

Compatible Tank Mates for Boesemani Rainbowfish

Because boesemani rainbowfish are mild-tempered, they get along well with many other fish. Characins, rasboras gouramis, danios, tiger barbs, corydoras, and other rainbowfish are all compatible tankmates for boesemani rainbowfish. When choosing tankmates for the boesemani rainbowfish it’s important to keep in mind that they’ll need to be housed with similar-sized fish.

Incompatible Tank Mates for Boesemani Rainbowfish

Although boesemani rainbowfish are generally peaceful, there are some fish that are not recommended to share a tank with. Boesemani rainbowfish are active fish that are known to make sharp movements and shouldn’t be kept in a tank with smaller fish, the hyperactive nature of these fish can stress out and intimidate smaller fish. Additionally, they shouldn’t be housed with fish that require soft water and/or a low pH (e.g., angelfish), as boesemani rainbowfish are more partial to hard, alkaline water.

Boesemani Rainbowfish Diseases

White Spot Disease and Velvet Disease are two of the most common diseases in rainbowfish, with both diseases being caused by parasites.

Ich (White Spot Disease)

Ich, also known as White spot disease, is caused by a parasite called Ichthyophthirius multifiliis that attaches itself to the body, fins, and gills of the boesemani rainbowfish. This disease causes the appearance of white spots to form all over the infected fish’s body. Boesemani rainbowfish with this disease may also start to swim erratically. White spot disease is often caused by not quarantining a new fish before adding it to a tank with other fish.

Velvet disease

Velvet disease is caused by a parasite called Oodinium pillularis, this disease causes the fish to develop spots and hairy specks that gives their skin a velvety appearance. In the initial stages of this disease a boesemani rainbowfish may rub their body against rocks and plants often and move around less.  Over time the physical effects of the disease will be noticeable, as the boesemani rainbowfish will look like their skin has a velvet layer.

Velvet disease is highly contagious, so it’s important to transfer any infected boesemani rainbowfish into a tank where they can isolate away from their tankmates.

A veterinarian can be consulted to prescribe boesemani rainbowfish a series of medications to treat this disease. To prevent velvet disease in boesemani rainbowfish, it’s crucial to avoid abrupt changes in water temperature or water pH, which can cause the appearance of parasites. As an added precaution, it’s best to quarantine any new fish in a separate tank before adding them to a community tank with boesemani rainbowfish.

Where Can I Find Boesemani Rainbowfish for sale?

Boesemani rainbowfish can be found online and in pet shops, throughout the U.S. Because these rainbowfish are largely bred in captivity, they’re not very difficult to find.

Boesemani Rainbowfish Price

Boesemani rainbowfish are relatively expensive, they can cost anywhere between $10 to $20 for each fish depending on their size. Some boesemani rainbowfish may be found at a lesser cost, although it’s important to note that not all breeding farms engage in the recommended practices necessary to raise healthy boesemani rainbowfish, which can result in their colors never reaching full vibrancy. Boesemani rainbowfish that are sold at a premium price from reputable pet stores are more likely to be healthier and more colorful in the long run.

Boesemani Rainbowfish as an Endangered Species

Boesemani rainbowfish are an endangered species and have been placed on the International Union for Conservation of Nature Red List of Threatened Species (IUCN Red List). Experts have cited environmental factors, over-harvesting, and poor management in the aquaculture farms they dwell in as some of the reasons boesemani rainbowfish are in danger of extinction. In addition to facing extinction, these beloved fish are experiencing an overall loss in coloration, which is why it’s critical to refrain from crossbreeding them.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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