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How Many Boesemani Rainbows Can You Keep in 75 Gallon Tank?

Boesemani rainbow fish are endemic to the Ayamaru lakes and tributaries near Bird’s Head Peninsula in Indonesia. With their vibrant colors and peaceful demeanor, they make a great addition to any large freshwater aquarium. If you’re thinking about keeping this species in your 75-gallon tank, you may be wondering how many to get?

As a type of shoaling fish, Boesemani rainbows need the company of others of their own kind to thrive in a captive environment. Therefore, it’s recommended that you keep at least 6 of the same species together in a community tank. For a 75-gallon aquarium, you can keep up to 12, if that’s all the fish you have. The bigger they are and the more fish you want, the larger the tank should be.

Now that you know you can keep a dozen Boesemani rainbow fish in a 75-gallon tank, let’s explore this topic further. I’ll explain how big these fish get, if they’re hardy or not, and what aquatic creatures make the best tank mates. I’ll also discuss what water conditions they need, the types of aquarium equipment required and what to feed them.

So, if you’re ready to learn more about keeping Boesemani rainbow fish, then let’s begin!

How Many Boesemani Rainbow Fish Should Be Kept Together?

Boesemani rainbow fish are shoaling in nature and prefer to be with others of their species. How many you should keep is mainly dependent on the size of your tank. As it’s often recommended that you keep at least 6 – 1 male with 5 females, if possible, as the males will often fight each other for territory and/or dominance over the females – the absolute minimum size aquarium would be a 30-gallon tank.

How Big Do Boesemani Rainbow Fish Get?

Boesemani rainbow fish can reach lengths of up to 6 inches in the wild and typically grow at a rate of 2 inches every 6 months. On average, however, full-grown males in captivity are usually about 4 inches long whereas as adult females only get about 3 inches long. This is one way of telling them apart, along with the fact that males tend to be wider in the body and more brightly colored than females.

Are Boesemani Rainbow Fish Hardy?

Boesemani rainbow fish are moderately hardy and fairly easy to care for. Water parameters are the key to their overall health. If the aquatic conditions aren’t accurate or properly maintained, these fish can develop columnaris, a bacterial infections characteristic of long hair-like strings that hang from their mouths and along their fins.

What Do You Need for a Tank with Boesemani Rainbow Fish?

Boesemani rainbow fish need a freshwater tank with tall, live plants like java fern or amazon sword and plenty of open space to swim about. They need a large tank – minimum 30 gallons but bigger it better! Since they’re a type of tropical fish, they require a warm aquatic environment. A heater in the aquarium is necessary with the temperature of 80- and 85-degrees Fahrenheit and a pH level between 7 and 8.

Check out these heaters available online through Amazon.

Sand (not gravel) is the recommended substrate for Boesemani rainbow fish as the fine grains are less likely to cause scrapes and scratches. Since these fish prefer slow-moving water, air and/or water pumps aren’t necessary however, a filter is. A cannister filter is best for larger tanks but a hang-on-back version will work also.

Check out these filters available online through Amazon.

An aquarium light is also required – not only for the fish but for the plants as well. Choose one with an LED bulb as it’ll improve viewing and enhance the bright red, blue and yellow hues of tropical fish like Boesemani rainbows. Set the timer to 8 hours on and 16 hours off. If your light has an ambient-blue setting, you can turn that on for a few hours at night to lengthen your viewing time.

Check out these aquarium lights available online through Amazon.

 FREE Boesemani Rainbow Fish

Can You Keep Boesemani Rainbow Fish in a 55-Gallon Tank?

If you can keep Boesemani rainbow fish in a 30-gallon tank, then you can also keep them in a 55-gallon tank. This species is active and likes to swim about freely in an aquarium so the bigger the tank, the better. If you have a 55-gallon tank only and want to raise Boesemani rainbows, then I’d suggest you get 6 to 8 with no more than 2 males. This will reduce stress and keep aggressive/territorial behavior at bay.

What is the Best Tank Size for Boesemani Rainbow Fish?

The best tank size for Boesemani rainbow fish is the biggest one possible! This species likes to forage and explore its aquatic environment so the more room, the better. If you’re keeping just Boesemani rainbows, then you don’t need quite as large of an aquarium – a 30-gallon version is fine for a shoal of 6. However, if a community tank is what you’re after, then you need at least a 75-gallon tank (or greater).

For a 75-gallon tank, some aquarium hobbyists have suggested 18 to 20 Boesemani rainbows but in my opinion, that’s too much. With that many fish, you’d need a top-notch filtration system running at peak performance (not to mention doing 30% to 35% water changes every other week) to keep the aquatic environment clean and safe! I’d recommend no more than 12 Boesemani rainbows for a 75-gallon tank.

If you have your heart set on 18 or more Boesemani rainbows, then be prepared to invest in a large tank – 90 gallons or bigger. To keep stress levels down and prevent territorial fighting, these fish need plenty of space. They also need room to swim together in groups. If you intend to breed this species and/or keep other fish in the tank as well, then you should consider a 125-gallon aquarium instead.

What is the Best Tank Size for Breeding Boesemani Rainbow Fish?

Boesemani rainbows spawn quite easily – it’s the care of the fry that can be tricky. Since they don’t eat their own offspring, you can breed and raise them in the same tank. For this, you’ll need a large tank, at least 75-gallons of more as the females will scatter anywhere from 20 to 60 eggs at a time! Make sure the tank is planted to provide cover and safety for hatchlings from other creatures that may eat them.

What Do Boesemani Rainbow Fish Eat?

Boesemani rainbow fish are omnivores, so they require a diet of both plant- and meat-based foods. They’re not picky eaters and will feast on just about anything edible in their tank! Their only limitation is their small mouths. This is great for tanks with invertebrates or snails as you won’t have to worry about them getting eaten!

Feed these fish once a day with enough food to be consumed in a 2- to 3-minute time-period. Offer a variety of edibles like tropical fish flakes and pellets, spirulina flakes, mosquito larvae, frozen brine shrimp and/or bloodworms, even tiny pieces of spinach or other leafy greens. They’ll also feast on the algae growing naturally in the tank.

What Can You Keep with Boesemani Rainbow Fish?

Boesemani rainbow fish have a peaceful demeanor and therefore do quite well in a community tank environment. Keeping them with others of their kind is recommended as well as fish of similar size and temperament. Cory catfish, danios, tiger barbs, larger species of tetra fish, and even other rainbows. You can even keep them with invertebrates such as ghost shrimp or assassin snails.

Boesemani Rainbow Fish


To conclude, Boesemani rainbows are a type of shoaling freshwater fish and need to be with others of their kind in an aquarium. It’s recommended they be kept in groups of at least 6 in a tank no smaller than 30 gallons. If you have a large, 75-gallon tank, you can double the amount and have 12 with 2 males and 10 females. Don’t keep too many males as they’ll likely fight each other for dominance.

I hope this article has answered your questions about Boesemani rainbow fish and many should be kept together. Thanks for reading and good luck with your aquarium hobby.

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