Mubi Rainbowfish
Melanotaenia mubiensis
A rare, energetic, and colorful schooling fish native to the clear, limestone-filtered streams of the Kikori River system in Papua New Guinea. As they mature, males develop striking colors and deep bodies. Like most rainbowfish, they are highly active, requiring long aquariums with moderate flow and moderately hard, alkaline water to thrive.
Mubi Rainbowfish At a Glance
Mubi Rainbowfish Tank Requirements
Will Mubi Rainbowfish fit in your tank?
Care guides tell you what Mubi Rainbowfish needs, the next question is whether your tank can safely provide it. Test Mubi Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.
Mubi Rainbowfish Water Parameters
Mubi Rainbowfish Temperament & Compatibility
Mubi Rainbowfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard / Unsexed
Typically sold as juveniles where sexing is difficult. They have a slender, silvery appearance that transforms dramatically as they mature into adults. Must be kept in a shoal of 6 or more to prevent stress and encourage natural behavior.
Differs in 1 trait from base species
Also known as: Juvenile
Male
Males develop significantly deeper bodies (taller profile), brighter coloration, and elongated dorsal and anal fins that overlap. They frequently 'flash' their colors to females and spar harmlessly with other males for hierarchy.
Differs in 3 traits from base species
Also known as: Show Male, Adult Male
Female
Females remain more slender and possess shorter, translucent fins with less brilliant body coloration. Maintaining a higher ratio of females to males (e.g., 2 females per 1 male) is recommended to disperse male breeding harassment.
Differs in 2 traits from base species
Also known as: Adult Female
Mubi Rainbowfish Care Guide Summary
The Mubi Rainbowfish, scientifically known as Melanotaenia mubiensis, 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 low level of biological waste.
To thrive, the Mubi Rainbowfish requires a freshwater only aquarium with a minimum volume of 110 litres and a tank length of at least 90 cm. Water temperature should be maintained between 24°C and 28°C, with a pH range of 7–8.2 and a general hardness of 8–20 dGH. A moderate water flow is preferred.
The Mubi Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Standard / Unsexed, Male, and Female. 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.
Mubi Rainbowfish Habitat Setup
When setting up an aquarium for the Mubi 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 dense planting to provide cover, break sightlines, and reduce stress. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Mubi Rainbowfish Compatibility Notes
Classified as peaceful, the Mubi 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, 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.
Who Mubi Rainbowfish Is Actually For
Mubi Rainbowfish is best for a fishkeeper who wants a species that can settle into a calmer community setup and can provide a keeper who can commit to a proper group of at least 6. It makes the most sense for a hobbyist who will actually build around its needs, especially plants.
The most common mistake is buying Mubi Rainbowfish for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is underestimating its social needs. A token pair or trio often behaves very differently from a real group.
Mubi Rainbowfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Mubi Rainbowfish.
30 Gallon Breeder
40 Gallon Breeder
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
Show 10 more tank sizes
Frequently Asked Questions About Mubi Rainbowfish
How big does Mubi Rainbowfish get?
Mubi Rainbowfish (Melanotaenia mubiensis) 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 Mubi Rainbowfish need?
A minimum aquarium volume of 110 litres and a tank length of at least 90 cm are recommended for Mubi Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Mubi Rainbowfish need?
Mubi Rainbowfish thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 7 and 8.2, and a general hardness of 8–20 dGH. A moderate water flow is preferred.
Is Mubi Rainbowfish peaceful or aggressive?
Mubi 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 Mubi Rainbowfish should be kept together?
Mubi 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 Mubi Rainbowfish have any special tank requirements?
Yes. Mubi Rainbowfish benefits from plants - densely covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Mubi Rainbowfish need a lid on the tank?
Yes. Mubi 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.
Useful setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- May 6, 2026
- Last updated
- May 6, 2026
- Issues or corrections?
- Contact the editorial team
Top Tank Mates for Mubi Rainbowfish
These fish are strong compatibility matches for Mubi Rainbowfish based on water preferences, temperament, adult size, and tank behavior.
Trapdoor Snail
Cipangopaludina chinensis
Ideal Tank MatesReticulated Stingray (Teacup Ray)
Potamotrygon orbignyi
Ideal Tank MatesTandanus Catfish
Tandanus tandanus
Ideal Tank MatesSkunk Cory
Corydoras arcuatus
Ideal Tank MatesSan Juan Cory
Corydoras bilineatus
Ideal Tank MatesPetricola Catfish
Synodontis petricola
Ideal Tank MatesPlants That Suit Mubi Rainbowfish
These plants pair well with Mubi Rainbowfish based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Afzel's Anubias
Anubias afzelii
Amazon Sword
Echinodorus amazonicus
Anacharis
Egeria densa
Anubias Barteri
Anubias barteri
Baby Tears
Lindernia rotundifolia
Balansae
Cryptocoryne crispatula
Fish Similar to Mubi Rainbowfish
Kabia rainbowfish
Glossolepis kabia
A rare and active schooling fish endemic to the Sepik and Ramu river basins of Papua New Guinea. Known for their silvery-green to blue iridescence, they inhabit slow-moving rivers, swampy lagoons, and oxbow lakes. Like most rainbowfish, they require ample horizontal swimming space and thrive in planted aquariums with stable, clean water.
Blue Rainbowfish
Melanotaenia caerulea
A small, highly active, and colorful schooling fish native to the Kikori River system in Papua New Guinea. They are peaceful but require ample swimming space and a school of their own kind to thrive. Like most rainbowfish, they appreciate well-oxygenated, flowing water and are excellent jumpers. Males develop a striking blue hue with reddish horizontal stripes.
Silver Rainbowfish
Chilatherina crassispinosa
An active, schooling rainbowfish native to the clear, fast-flowing streams of Northern New Guinea. Known for their energetic swimming patterns and silvery bodies, they require long aquariums with strong water flow and high dissolved oxygen. Best kept in groups of 6 or more.
Goldie River Rainbowfish
Melanotaenia goldiei
The Goldie River Rainbowfish is a vibrant, highly active schooling fish native to the clear rainforest streams and backwaters of southern New Guinea. As rapid swimmers, they require significant open swimming space. They are voracious mid-water and surface feeders that will readily eat insects and standard aquarium foods. While peaceful, their exuberant energy can intimidate shy tank mates.
Bulolo Rainbowfish
Chilatherina bulolo
A rare and highly active rainbowfish native to the fast-flowing mountain streams and white-water rapids of the Markham and Ramu river systems in Papua New Guinea. They possess a silvery body with a distinct black streak on the upper and lower edges of the caudal fin. Because of their specialized natural habitat, they require highly oxygenated, fast-flowing water and alkaline conditions to thrive in an aquarium.
New Guinea Rainbowfish
Melanotaenia affinis
An active, schooling species native to the streams of northern New Guinea. Known for their striking lateral stripe and vibrant fin coloration that flashes during morning displays. They are peaceful but highly energetic, requiring ample open swimming space and highly oxygenated water to thrive.