Allen's rainbowfish
Chilatherina alleni
A Western Papuan rainbowfish with turquoise, yellow and orange reflections that intensify in dominant males during morning displays. Native to the Wapoga and Siriwo river systems in eastern Indonesia, it is an active and tireless swimmer that needs open space in the tank's mid-zone. In groups of 6–8+ with proper lighting and dark substrate, males rival each other in spectacular chromatic displays. Hardy and adaptable, it is an excellent choice for beginner-to-intermediate hobbyists seeking lively, colorful fish. An enthusiastic omnivore that accepts virtually any food.
Water Temperature
24 - 28 °C
pH Value
7 - 8
Water type
Freshwater
Tank level
Middle
Adult size
10 cm
Minimum tank volume
>= 200 L
Minimum group
>= 6
GH
8 - 15 dGH
KH
4 - 7 dKH
TDS
160 - 295 ppm
Conductivity
250 - 461 uS/cm
Species description
Geographical Origin and Habitat: Endemic to the streams of the peninsula north of the Siriwo River, in Irian Jaya (Indonesian New Guinea). Populates clear streams amidst dense forests, with patchy sun exposure.
Taxonomy and Morphology: Allen's Rainbowfish (Chilatherina alleni). Rainbowfish belonging to the Melanotaeniidae family. Rather massive, reaches 10 cm (4 inches). Like all Chilatherina, the head profile is pointed, suited for surface predation.
Social Behavior: Very active schooling fish. Males engage in dominance "displays" by pulling up alongside each other, darkening some stripes and vibrating, a continuous but rarely lethal spectacle. They must be in a group of at least 6-8.
Coloration and Sexual Dimorphism: Males (especially the "Wapoga" variant) boast a flaming red upper back that fades into an iridescent blue on the flanks, interrupted by stripes. Females are silver-gray, thinner and without the bright reflections.
Care, breeding and tankmates
Aquarium Setup: Minimum 100 cm (40 inches) in length. Rainbowfish are tireless swimmers. Dense planting in the background, branched wood, but essential to provide 2/3 of the tank with bright light and open space for swimming.
Diet and Feeding: Omnivore with a carnivorous predilection (fallen insects). Easily accepts high quality feeds (floating or semi-sinking granules), freeze-dried and live (brine shrimp, mosquito larvae).
Water Quality: Thrive in neutral or slightly alkaline and hard waters (pH 7.0-8.0, GH 8-15). Intolerant to old and acidic waters. Weekly 30% water changes are fundamental to stimulate colors and health.
Compatibility and Cohabitation: Excellent inhabitant for medium-sized community tanks. Perfect together with Tateurndina, other Melanotaeniids, Botia or Loricariids. Too restless to coexist with Discus or slow fish.
Aquarium Breeding: Serial breeders. In planted tanks (moss or mop) they lay a few eggs a day. The eggs take about 7-10 days to hatch. Adults will ignore the young if very well fed, but it is better to separate the mop.
Risks and Diseases: The appearance of spinal deformities or skin ulcers is the first symptom of "Mycobacterium marinum" (Fish Tuberculosis) to which Rainbowfish are genetically exposed if water cleanliness degenerates.
Geographic Origin and Distribution
Endemic to the streams of the peninsula north of the Siriwo River, in Irian Jaya (Indonesian New Guinea). Populates clear streams amidst dense forests, with patchy sun exposure.
Origin
Africa and MadagascarSouth and Southeast AsiaAustralia, New Guinea, and Oceania
Fish profile
- Temperament
- Peaceful
- They are exuberant, highly social, and completely non-aggressive fish. Their flashing movements provide stunning dynamic energy to displays. They are incredibly hardy, making them perfect for beginners.
- Diet
- Omnivore
- They are completely unfussy omnivores eating almost anything offered. Tropical flakes, micro-pellets, and frozen bloodworms are highly recommended. Spirulina significantly enhances their spectacular blue and yellow colors.
- Life expectancy
- 5-8 years
- Has an average lifespan of 5 to 8 years in the aquarium under optimal care. Maintaining clean, highly oxygenated water with regular water changes is essential for their longevity. Proper aquarium management prevents common skin infections and supports general health.
- Adult size
- 10 cm
- The catalog's scalar value is 10 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 6.6 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Chilatherina alleni (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- School
- To encourage natural schooling behavior and vibrant coloration, Chilatherina alleni should be kept in groups with a specific sex ratio leaning towards females. An ideal ratio is generally one male to every two or three females to help distribute the males' vigorous breeding harassment. Keeping multiple males is possible and often results in spectacular displaying behaviors, provided the school size is large enough (8-10+ individuals) to diffuse aggression. Failing to provide enough females can lead to severe stress and exhaustion for the subordinate fish.
- Feeding frequency
- Twice daily
- One or two small meals perfectly suit their energy. They snap up falling morsels with explosive, enthusiastic speed. Ensure slower bottom-dwelling fish receive their fair daily share.
- Bioload
- Medium
- Allen's rainbowfish produce a very manageable metabolic bioload. Their highly active lifestyle demands excellent, pristine water quality. A well-maintained canister filter keeps their environment perfectly clean.
- Flow
- Strong
- They inhabit clear, fast-flowing natural rivers in New Guinea. They absolutely thrive with strong currents and surface agitation. Strong flow actively encourages their vigorous, natural schooling behaviors.
- Jump risk
- Yes
- Allen's rainbowfish are highly active, open-water swimmers with a significant risk of jumping, particularly when startled or engaged in frantic feeding frenzies. They possess streamlined bodies built for swift currents, enabling them to easily breach the water's surface if they build up enough momentum. Spawning rituals at the surface, playful chasing, or sudden shadows passing over the tank can frequently result in airborne fish. A tight-fitting lid or a heavy glass canopy is completely mandatory to prevent these energetic fish from jumping out.
- Reproduction
- Oviparous
- They continuously scatter adhesive eggs daily among fine plants. Parents show no care and actively eat their fry. Use a dedicated spawning mop for successful controlled breeding.
- Compatibility & tankmates
- Peaceful
- They are outstandingly peaceful medium-sized community aquarium fish. They coexist happily with tetras and bottom-dwelling peaceful catfish. Their incredibly fast speed might intimidate very shy tankmates.
- Tank level
- Middle
- This species predominantly occupies the upper and middle levels of the aquarium, continuously swimming in the open water sections. They are highly buoyant, active foragers that readily investigate the water surface for floating insects and prepared foods. While they will occasionally dive to the lower third of the tank to inspect plant thickets, their true home is the unobstructed upper water column. Providing immense lateral swimming space free of tall decorations is crucial to cater to their athletic, surface-oriented lifestyle.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2.9 ± 0.4 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5005
- Bayesian Length-Weight
- a = 0.00389, b = 3.12
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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