A beautiful, highly active shoaling fish native to the rainforest streams of West Papua, Indonesia. Known for their striking mauve bodies, bold blue lateral bands, and red fins with white margins. They are fast, robust swimmers that require plenty of open horizontal space and a tight-fitting lid to prevent jumping. While peaceful, their voracious eating habits and speed can easily outcompete shy or slow-moving tank mates.
Irian Jaya Rainbowfish At a Glance
Irian Jaya Rainbowfish Tank Requirements
Will Irian Jaya Rainbowfish fit in your tank?
Care guides tell you what Irian Jaya Rainbowfish needs, the next question is whether your tank can safely provide it. Test Irian Jaya Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.
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Irian Jaya Rainbowfish Water Parameters
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Irian Jaya Rainbowfish Temperament & Compatibility
Irian Jaya Rainbowfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Juvenile / Unsexed
Typically sold in stores as juveniles, presenting a relatively drab, silvery appearance. Their spectacular colors and physical dimorphism develop as they mature and establish a pecking order.
Same care requirements as the base species
Also known as: Juvenile Rainbowfish, Standard
Male
Mature males develop a significantly deeper, arched body, elongated dorsal and anal fins, and vibrant colors (mauve/blue with red fins) to attract females. They frequently 'flash' their colors and spar harmlessly with other males for dominance.
Same care requirements as the base species
Also known as: Show Male, Adult Male
Female
Females remain more streamlined (slender) than males and possess shorter, rounded fins. Their coloration is far less intense, consisting mostly of silver or yellowish hues.
Differs in 1 trait from base species
Also known as: Adult Female
Irian Jaya Rainbowfish Care Guide Summary
The Irian Jaya Rainbowfish, scientifically known as Melanotaenia irianjaya, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 10 cm and have a fusiform 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 Irian Jaya Rainbowfish requires a freshwater only aquarium with a minimum volume of 85 litres and a tank length of at least 90 cm. Water temperature should be maintained between 23°C and 28°C, with a pH range of 6.5–8 and a general hardness of 5–15 dGH. A moderate water flow is preferred.
The Irian Jaya Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Juvenile / 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.
Irian Jaya Rainbowfish Habitat Setup
When setting up an aquarium for the Irian Jaya 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.
Irian Jaya Rainbowfish Compatibility Notes
Classified as peaceful, the Irian Jaya 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.
Irian Jaya Rainbowfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Irian Jaya Rainbowfish.
30 Gallon Breeder
40 Gallon Breeder
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
Show 10 more tank sizes
Irian Jaya Rainbowfish Feeding & Diet Considerations
The Irian Jaya Rainbowfish will eat fry, so breeding efforts in the same tank are unlikely to succeed and is an aggressive eater that may prevent timid tankmates from getting enough food, so target feeding or simultaneous feeding at opposite ends of the tank can help.
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Frequently Asked Questions About Irian Jaya Rainbowfish
How big does Irian Jaya Rainbowfish get?
Irian Jaya Rainbowfish (Melanotaenia irianjaya) typically reaches a maximum adult size of approximately 10 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Irian Jaya Rainbowfish need?
A minimum aquarium volume of 85 litres and a tank length of at least 90 cm are recommended for Irian Jaya Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Irian Jaya Rainbowfish need?
Irian Jaya Rainbowfish thrives in freshwater only conditions with a temperature range of 23–28°C, a pH between 6.5 and 8, and a general hardness of 5–15 dGH. A moderate water flow is preferred.
Is Irian Jaya Rainbowfish peaceful or aggressive?
Irian Jaya 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 Irian Jaya Rainbowfish should be kept together?
Irian Jaya 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 Irian Jaya Rainbowfish have any special tank requirements?
Yes. Irian Jaya Rainbowfish benefits from plants - densely covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Irian Jaya Rainbowfish need a lid on the tank?
Yes. Irian Jaya 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 Irian Jaya Rainbowfish
These fish are strong compatibility matches for Irian Jaya Rainbowfish based on water preferences, temperament, adult size, and tank behavior.
Orange Delight Shrimp
Caridina loehae
Ideal Tank MatesMottled Loach
Paracanthocobitis botia
Ideal Tank MatesSchwartz's Cory
Corydoras schwartzi
Ideal Tank MatesLeopard Cory
Corydoras leopardus
Ideal Tank MatesGold Laser Cory
Corydoras sp. 'CW010'
Ideal Tank MatesDainty Cory (Salt and Pepper Cory)
Corydoras habrosus
Ideal Tank MatesPlants That Suit Irian Jaya Rainbowfish
These plants pair well with Irian Jaya 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 Irian Jaya Rainbowfish
Allen's Rainbowfish
Chilatherina alleni
A rare and highly active rainbowfish native to West Papua, Indonesia (Wapoga River basin). Known as the 'Wapoga Rainbowfish', they undergo a dramatic color transformation as they mature, developing intense metallic blues, greens, and reds. As exceptionally fast, continuous swimmers, they require a 4-foot (120cm) aquarium minimum to thrive without stress.
Batanta Rainbowfish
Melanotaenia batanta
A stunning, active shoaling fish endemic to Batanta Island in West Papua, Indonesia. They inhabit clear, moderately fast-flowing rainforest streams. Like most rainbowfish, they are highly social, energetic swimmers that require plenty of horizontal swimming space and clean, well-oxygenated water. Males exhibit striking blueish coloration with narrow orange stripes. The species is considered Vulnerable in the wild.
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.
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.
Exquisite Rainbowfish
Melanotaenia exquisita
A highly active, schooling species native to the fast-flowing, clear streams of Australia's Northern Territory. True to their name, they display stunning metallic bodies with bright red-tipped fins. They require pristine, well-oxygenated water, plenty of horizontal swimming space, and should always be kept in groups of 6 or more.
Leggett's Rainbowfish
Glossolepis leggetti
A rare and highly active schooling fish native to the Wapoga and Tiawiwa River systems in West Papua, Indonesia. Known for its distinct sexual dimorphism as it matures, with males developing a deep arch and striking green/blue iridescence. Like most rainbowfish, they require highly oxygenated water, moderate flow, and significant horizontal swimming space.