Phoenix rasbora
Boraras merah
A micro-rasbora with vivid red-orange coloration and dark lateral spots, native to the blackwater peat swamps of Borneo. Closely related to the chili rasbora (B. brigittae) but with a slightly different color pattern — more orange-red with defined spots rather than a continuous band. Requires soft, acidic water (pH 4.0–6.5), ideally achieved with remineralized RO water, and a dark, tannin-rich environment. In schools of 15–20+ on dark substrate, coloration reaches a hypnotic intensity. A perfect companion for dedicated Borneo blackwater nano aquariums.
Wassertemperatur
24 - 28 °C
pH-Wert
4 - 6.5
Wassertyp
Süßwasser
Tankfüllstand
Oberfläche und Mitte
Erwachsenengröße
2 cm
Mindesttankvolumen
>= 40 L
Mindestgruppe
>= 10
GH
1 - 10 dGH
KH
7 - 14 dKH
TDS
85 - 290 ppm
Leitfähigkeit
133 - 453 uS/cm
Artbeschreibung
Geographical Origin and Habitat: Endemic to the Jelai and Kahayan river basins in southern Borneo (Indonesia). Inhabits peat swamps where dark, slow-moving water makes its way through submerged roots and dense blankets of organic material.
Taxonomy and Morphology: Phoenix Rasbora (Boraras merah). "Merah" in Indonesian means "red". Very similar to B. brigittae with which it is sympatric (they live in the same habitat and are often caught together), but it has a broken lateral pattern instead of a solid line.
Social Behavior: Of an extremely gregarious nature, it must live in schools formed by a minimum of 15-20 individuals. In smaller groups it will become apathetic, lose its colors and tend to hide perpetually under the leaves.
Coloration and Sexual Dimorphism: Reddish-orange background (less intense than the blood-red of brigittae). In the center of the body there is a large dark oval spot, surrounded by a bright red halo (hence the name Phoenix), followed by disjointed black spots towards the tail.
Pflege, Zucht und Mitbewohner
Aquarium Setup: Ideal for a 20-30 liters (5-8 gallons) Nano-cube. Needs a densely planted "Blackwater" layout, with a dark sand or soil bottom, abundance of woods and very light mechanical filtration. Amber water through alder cones.
Diet and Feeding: In nature it hunts microorganisms in the dense foliage. In the aquarium, the staple food must be tiny live food: brine shrimp nauplii, microworms and daphnia. Accepts powdered dry food but in the long run it fades the coloration.
Water Quality: The ideal water is very soft and acidic (pH 4.0-6.5), amber and rich in tannins to prevent bacterial infections. An increase in nitrogenous compounds is lethal to the species.
Compatibility and Cohabitation: Perfect in a dedicated tank. Excellent tankmate for Neocaridina, small Otocinclus, and dwarf Corydoras. Categorically avoid active fish over 4 cm (1.5 inches) in size, which could mistake it for food.
Aquarium Breeding: Continuous spawner that scatters a few eggs daily among mosses (Taxiphyllum). The eggs are lucifugous (they fear strong light). If the tank is dense and mature, a few fry will survive without care.
Risks and Diseases: Threatened in the wild by rapid urbanization and the conversion of its habitat into rubber and palm oil plantations. In the aquarium, it risks being sucked into the filter and occlusions if fed with food that is too large.
Geografische Herkunft und Verbreitung
Endemic to the Jelai and Kahayan river basins in southern Borneo (Indonesia). Inhabits peat swamps where dark, slow-moving water makes its way through submerged roots and dense blankets of organic material.
Ursprung
Süd- und SüdostasienOstasien
Fischprofil
- Temperament
- Territorial
- This is an extremely peaceful, timid, and schooling species that only feels secure when kept in large numbers. Males may display mild and temporary territoriality during spawning periods, engaging in harmless sparring displays to impress females. Their reserved nature makes them unsuitable for tanks with large or boisterous fish, which can easily intimidate them and force them into hiding.
- Diät
- Carnivore
- In the wild, *Boraras merah* is a micro-predator feeding on small insects, worms, crustaceans, and other zooplankton in blackwater biotopes. In captivity, they will accept high-quality crushed flakes and micropellets, but they require live and frozen micro-foods to display their best colors and maintain vitality. Foods such as baby brine shrimp, daphnia, microworms, and copepods are ideal and easily consumed by their tiny mouths.
- Lebenserwartung
- 3-5 years
- Erwachsenengröße
- 2 cm
- Geschlechterverhältnis
- Group
- This species does not require a strict male-to-female ratio and benefits most from being kept in a large group of at least eight to ten individuals. Within the shoal, the presence of multiple males encourages healthy intraspecific competition, prompting them to display their most intense spawning colors and fascinating sparring behaviors. Females, which are typically rounder and slightly less colorful, help balance the group dynamics and reduce overall stress for individual fish.
- Fütterungsfrequenz
- Twice daily
- Given their small size and rapid metabolic rate, it is best to feed them small amounts two to three times a day rather than one large feeding. This feeding schedule ensures that all individuals receive adequate nutrition and minimizes uneaten food that could spoil the water. Regular small feedings also mimic their natural foraging behavior of searching for food throughout the day.
- Bioload
- Low
- Due to its exceptionally minuscule size, rarely exceeding two centimeters in length, *Boraras merah* contributes a negligible biological load to the aquarium. However, because they must be kept in sizable groups to thrive, the overall filtration system should be efficient yet gentle. Sponge filters or air-driven systems are ideal to prevent these tiny fish from being sucked into the filter intake while maintaining excellent water quality free of harmful nitrogenous compounds.
- Fluss
- Strong
- Hailing from sluggish peat swamps and slow-flowing forest streams, this species prefers weak to moderate water flow. A strong current will quickly exhaust these tiny fish, forcing them to constantly battle the flow and causing severe stress. Using a filter output directed against the glass or baffled by dense plants helps create calm zones where the fish can rest comfortably.
- Sprungrisiko
- Yes
- While not notorious high-jumpers, *Boraras merah* can easily leap out of the water if startled by sudden movements, lights turning on, or during acclimation. It is therefore essential to provide a tight-fitting lid or cover slides on the aquarium, or utilize a dense cover of floating plants to secure the surface. These measures not only prevent fatal accidents but also make the fish feel secure and less prone to stress-induced flight.
- Reproduktion
- Oviparous
- Breeding *Boraras merah* is moderately accessible, as they are egg-scatterers that exhibit no parental care and spawn continuously. While some fry may survive in a mature, densely planted community tank, a dedicated breeding setup with soft, acidic water is recommended for higher yields. The adult pair or group should be removed shortly after spawning to prevent them from eating the eggs, and the fry must be fed microscopic foods like infusoria or paramecia initially.
- Kompatibilität & Tankkameraden
- Peaceful
- This tiny cyprinid is perfect for species-only setups or community tanks populated by similarly small, peaceful tankmates. Excellent companions include other *Boraras* species, micro-rasboras, dwarf corydoras, freshwater shrimp like *Neocaridina*, and peaceful snails. It is imperative to avoid keeping them with large, aggressive, or hyperactive fish that could easily mistake them for food or stress them out.
- Tankfüllstand
- Top/Middle
- Within the aquarium, the Phoenix rasbora prefers to occupy the middle and upper levels of the water column. In these areas, they swim in coordinated shoals under the safety of plant cover or floating vegetation that diffuses the light. Despite this preference, they are curious explorers and will occasionally venture to the bottom of the tank to forage for food scraps among the substrate and decor.
Wissenschaftliche Modelle & Parameter
FishBase
Zugang zu den offiziellen wissenschaftlichen Daten der Art
FishBase v25.04Daten synchronisiert am: 15.06.2026
- Trophäenniveau
- 3,1 ± 0,4 se
- Belastbarkeit
- Hoch (weniger als 15 Monate)
- Phylogenetische Einzigartigkeit (PD50)
- 0.5156
- Bayessche Längen-Gewichts-Beziehung
- a = 0.00589, b = 3.08
- AnfälligkeitGeringe Anfälligkeit (10 / 100)
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