An incredibly popular and active schooling fish endemic to the Ajamaru Lakes in West Papua, Indonesia (currently listed as Endangered in the wild by the IUCN due to overfishing and habitat loss, though commercially captive-bred). Famous for the mature male's spectacular blue and orange split-coloration. They require long tanks for active swimming, excellent oxygenation, and warm, hard, alkaline water to thrive.
At a Glance
Tank Requirements
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Water Parameters
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Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Male
Adult males develop a highly arched back (deep body) and the iconic two-tone coloration: a bluish-purple front half and a vibrant orange-yellow rear. They continuously display to females and spar harmlessly with rival males. Best kept in a ratio of 1 male to 2 females, or in large groups.
Differs in 1 trait from base species
Also known as: Show Male, Adult Male
Female
Females are slightly smaller, more streamlined, and have subdued coloration (mostly silver/grey with yellowish fins and faint horizontal stripes). Keeping a proper female-heavy ratio reduces harassment stress and brings out the males' most intense display colors.
Differs in 1 trait from base species
Also known as: Female
Unsexed Juvenile
Most commonly found in stores at 3-5cm. Juveniles of both sexes are relatively colorless and silvery. It takes several months of high-quality diet and pristine water conditions for males to develop their characteristic deep body shape and dramatic colors.
Differs in 1 trait from base species
Also known as: Baby, Juvenile
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🟢Ideal Tank MatesBoeseman's Rainbowfish Care Guide Summary
The Boeseman's Rainbowfish, scientifically known as Melanotaenia boesemani, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 10 cm and have a compressed body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the surface and mid-level zones of the aquarium and produces a medium level of biological waste.
To thrive, the Boeseman's Rainbowfish requires a freshwater only aquarium with a minimum volume of 200 litres and a tank length of at least 120 cm. Water temperature should be maintained between 26°C and 30°C, with a pH range of 7–8.1 and a general hardness of 9–19 dGH. A moderate water flow is preferred. An aquarium test kit can help you monitor these values.
The Boeseman's Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Male, Female, and Unsexed Juvenile. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Boeseman's Rainbowfish Habitat Setup
When setting up an aquarium for the Boeseman's Rainbowfish, a moderate water flow best suits their natural preferences. Because this species occupies the surface and mid-level zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include light plant coverage for partial shade. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Boeseman's Rainbowfish Compatibility Notes
Classified as peaceful, the Boeseman's Rainbowfish is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, shy or slow-feeding tankmates may be outcompeted at feeding time and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the surface and mid-level zones can help reduce competition and territorial overlap.
Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Boeseman's Rainbowfish.
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
Frequently Asked Questions About Boeseman's Rainbowfish
How big does Boeseman's Rainbowfish get?
Boeseman's Rainbowfish (Melanotaenia boesemani) typically reaches a maximum adult size of approximately 10 cm. They have a compressed body shape and a moderate growth rate.
What tank size does Boeseman's Rainbowfish need?
A minimum aquarium volume of 200 litres and a tank length of at least 120 cm are recommended for Boeseman's Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Boeseman's Rainbowfish need?
Boeseman's Rainbowfish thrives in freshwater only conditions with a temperature range of 26–30°C, a pH between 7 and 8.1, and a general hardness of 9–19 dGH. A moderate water flow is preferred.
Is Boeseman's Rainbowfish peaceful or aggressive?
Boeseman's Rainbowfish is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.
How many Boeseman's Rainbowfish should be kept together?
Boeseman's Rainbowfish is a schooling species and should be kept in groups of at least 6. Larger groups help distribute aggression and encourage natural schooling behaviour.
Does Boeseman's Rainbowfish have any special tank requirements?
Yes. Boeseman's Rainbowfish benefits from plants - lighly covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Boeseman's Rainbowfish need a lid on the tank?
Yes. Boeseman's Rainbowfish is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Similar Species
Turquoise Rainbowfish
Melanotaenia lacustris
A stunning, deep-bodied rainbowfish endemic to Lake Kutubu in Papua New Guinea. Famous for their ability to shift colors from deep teal to bright iridescent blue depending on mood and water quality. They are active schooling fish that thrive in hard, alkaline water.
Red Rainbowfish
Glossolepis incisus
Native to Lake Sentani in Indonesia, this species is famous for the brilliant salmon-red coloration of mature males. They are large, active schooling fish that develop a distinct high-arched back as they age. Females are vastly different in appearance (olive-gold). They require hard, alkaline water and plenty of swimming space.
Celebes Rainbowfish
Marosatherina ladigesi
An active, schooling fish native to the karst (limestone) streams of Sulawesi, Indonesia. Known for their striking neon blue lateral stripes and yellowish fins. They strictly require hard, alkaline water to thrive and are highly sensitive to soft, acidic conditions. A peaceful species that requires plenty of open swimming space.
Dwarf Neon Rainbowfish (Praecox)
Melanotaenia praecox
A brilliant, active schooling fish native to the Mamberamo River basin in West Papua. Known for their iridescent neon-blue bodies, they are an energetic and peaceful addition to community tanks. Because of their high activity levels, they require ample open swimming space alongside planted areas. They are fast eaters and may outcompete shy tank mates for food.
Threadfin Rainbowfish
Iriatherina werneri
A delicate and exquisitely shaped nano rainbowfish native to New Guinea and Northern Australia. They are famous for the males' long, filamentous fins and butterfly-like display behavior. Due to their incredibly small throats, they require micro-foods. They are shoaling fish that are easily intimidated by boisterous tank mates.
Rosy Barb
Pethia conchonius
A hardy, active, and colorful subtropical schooling fish. Known for the male's striking rosy-red breeding dress, while females are more golden/silver. They are voracious eaters, very active swimmers, and can be fin-nippers if kept in too small a group. Best kept in cooler water compared to tropical species. The Long Finned morph is also popular but requires gentler flow.