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.
Useful setup supplies
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Arfak Rainbowfish Water Parameters
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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.
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
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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.
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.
Bandit Cory
Corydoras metae
Ideal Tank MatesAsher Cory
Corydoras tukano
Ideal Tank MatesPanda Garra
Garra flavatra
Ideal Tank MatesJulii Corydoras (False Julii)
Corydoras trilineatus
Ideal Tank MatesBristlenose Pleco
Ancistrus cf. cirrhosus
Ideal Tank MatesClown Loach
Chromobotia macracanthus
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
Banded Rainbowfish
Melanotaenia trifasciata
A large, robust, and highly active schooling fish native to Northern Australia. Famous for its intense geographic color variations (such as the red 'Goyder River' morph). They are peaceful but incredibly fast and vigorous swimmers, requiring long aquariums with plenty of open swimming space.
Boeseman's Rainbowfish
Melanotaenia boesemani
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.
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.
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.
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.
Axelrod's Rainbowfish
Chilatherina axelrodi
A highly active, colorful schooling fish native to Papua New Guinea. Known for a bluish-grey upper body and yellowish-white lower body divided by a dark lateral stripe. Like most rainbowfish, they are incredibly fast, active swimmers that require pristine water, moderate flow, and significant horizontal swimming space.