Arfak Rainbowfish
Melanotaenia arfakensis
A lively and relatively rare schooling fish endemic to the fast-flowing streams of the Bird's Head Peninsula in West Papua. Known for their energetic swimming and beautiful subtle coloration, with dominant males displaying bright orange-red fins edged in black. As active swimmers, they require long aquariums with high oxygenation and moderate to high water flow.
Arfak Rainbowfish At a Glance
Arfak Rainbowfish Tank Requirements
Will Arfak Rainbowfish fit in your tank?
Care guides tell you what Arfak Rainbowfish needs, the next question is whether your tank can safely provide it. Test Arfak Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.
Arfak Rainbowfish Water Parameters
Arfak Rainbowfish Temperament & Compatibility
Arfak Rainbowfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Male
Males grow larger and develop a significantly deeper, stockier body profile as they mature. They feature striking orange-red fins with pronounced dark margins and a silvery-purple sheen when displaying.
Differs in 1 trait from base species
Also known as: Male Arfak, Standard
Female
Females are noticeably smaller and maintain a much more slender, streamlined profile throughout their lives. Their coloration is subdued with mostly translucent fins. A mixed-sex school is essential to witness natural male display behaviors.
Differs in 1 trait from base species
Also known as: Female Arfak
Arfak Rainbowfish Care Guide Summary
The Arfak Rainbowfish, scientifically known as Melanotaenia arfakensis, 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 mid-level and surface zones of the aquarium and produces a low level of biological waste.
To thrive, the Arfak 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 24°C and 28°C, with a pH range of 7–8 and a general hardness of 5–15 dGH. A high water flow is preferred.
The Arfak Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 2 varieties: 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.
Arfak Rainbowfish Habitat Setup
When setting up an aquarium for the Arfak Rainbowfish, a high water flow best suits their natural preferences. Because this species occupies the mid-level and surface 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 smooth gravel or rounded substrate to protect their sensitive barbels and light plant coverage for partial shade. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Arfak Rainbowfish Compatibility Notes
Classified as peaceful, the Arfak 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 mid-level and surface zones can help reduce competition and territorial overlap.
Who Arfak Rainbowfish Is Actually For
Arfak 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 Arfak 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.
Arfak Rainbowfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Arfak Rainbowfish.
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
Frequently Asked Questions About Arfak Rainbowfish
How big does Arfak Rainbowfish get?
Arfak Rainbowfish (Melanotaenia arfakensis) 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 Arfak Rainbowfish need?
A minimum aquarium volume of 200 litres and a tank length of at least 120 cm are recommended for Arfak Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Arfak Rainbowfish need?
Arfak Rainbowfish thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 7 and 8, and a general hardness of 5–15 dGH. A high water flow is preferred.
Is Arfak Rainbowfish peaceful or aggressive?
Arfak 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 Arfak Rainbowfish should be kept together?
Arfak 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 Arfak Rainbowfish have any special tank requirements?
Yes. Arfak Rainbowfish benefits from plants - lighly covered and smooth gravel (sensitive barbels) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Arfak Rainbowfish need a lid on the tank?
Yes. Arfak 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
- April 29, 2026
- Last updated
- April 29, 2026
- Issues or corrections?
- Contact the editorial team
Top Tank Mates for Arfak Rainbowfish
These fish are strong compatibility matches for Arfak Rainbowfish based on water preferences, temperament, adult size, and tank behavior.
Reticulated Stingray (Teacup Ray)
Potamotrygon orbignyi
Ideal Tank MatesTandanus Catfish
Tandanus tandanus
Ideal Tank MatesSkunk Cory
Corydoras arcuatus
Ideal Tank MatesPetricola Catfish
Synodontis petricola
Ideal Tank MatesMottled Loach
Paracanthocobitis botia
Ideal Tank MatesSchwartz's Cory
Corydoras schwartzi
Ideal Tank MatesPlants That Suit Arfak Rainbowfish
These plants pair well with Arfak Rainbowfish based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
African Water Fern
Bolbitis heudelotii
Capuron's Aponogeton
Aponogeton capuronii
Madagascar Lace Plant
Aponogeton madagascariensis
Boivin's Aponogeton
Aponogeton boivinianus
African Onion Plant
Crinum calamistratum
Afzel's Anubias
Anubias afzelii
Fish Similar to Arfak Rainbowfish
Angfa Rainbowfish
Melanotaenia angfa
A beautiful and active schooling fish native to the Yakati River system in West Papua. Named in honor of the Australia New Guinea Fishes Association (ANGFA). Like many large rainbowfish, they are vigorous swimmers that require long aquariums to thrive. They display their best colors in well-planted tanks with clean, well-oxygenated water.
Sepik Rainbowfish
Glossolepis multisquamata
The Sepik Rainbowfish, also known as the Rosy Rainbowfish, is a vibrant schooling fish native to the floodplains, swampy lagoons, and slow-moving rivers of New Guinea. They are highly active swimmers that display stunning metallic and red coloration. They thrive in densely planted aquariums with ample open swimming space and require a group to feel secure and display their best colors.
Waigeo Rainbowfish
Melanotaenia catherinae
A rare but beautiful schooling fish endemic to the streams and springs of Waigeo Island in West Papua, Indonesia. They are highly active, energetic mid-water swimmers. Like most rainbowfishes, they are peaceful and thrive in planted community tanks that still offer plenty of open swimming space. They display a distinctive, unusually wide mid-lateral stripe and reddish fins.
Mountain Rainbowfish
Melanotaenia monticola
A striking and active schooling fish endemic to the high-altitude, fast-flowing mountain streams of Papua New Guinea. Because of their natural habitat, they are unique among Rainbowfish for requiring significantly cooler, highly oxygenated water. They feature a blue-grey to greenish body with a distinct black mid-lateral stripe and coppery golden scale margins.
Kamaka Rainbowfish
Melanotaenia kamaka
Endemic to the karst Lake Kamakawai in West Papua, this is a spectacular and distinctively deep-bodied rainbowfish. As they mature, males develop a robust chest and an intense silvery-blue to purplish sheen. Like all rainbowfish, they are highly active, schooling fish that require spacious tanks with plenty of horizontal swimming room and alkaline, hard water parameters.
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.