Dwarf rasbora
Boraras maculatus
One of the smallest fish in the trade (2–2.5 cm): a red-orange jewel with a large dark lateral spot on a translucent body. Native to blackwater peat swamps of the Malay Peninsula and Sumatra. In schools of 8–10+ the colorful micro-swarm is hypnotic. Requires soft, acidic water — loses color in hard water. Dark substrate and floating plants enhance colors. Micropredator with tiny mouth. Ideal for planted nano-aquariums. Longevity 2–5 years.
Température de l’eau
22 - 28 °C
Valeur du pH
4 - 6.5
Type d'eau
Eau douce
Niveau dans le bac
Surface et milieu
Taille adulte
2,5 cm
Volume minimal du bac
>= 20 L
Groupe minimal
>= 8
GH
1 - 8 dGH
KH
7 - 14 dKH
TDS
85 - 260 ppm
Conductivité
133 - 406 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Widely distributed in Southeast Asia (Peninsular Thailand, East Malaysia, Singapore, Sumatra). Inhabits peat swamps (blackwater) and river inlets closely associated with the ancient pristine rainforest.
Taxonomy and Morphology: Dwarf Rasbora (Boraras maculatus). "Maculatus" refers to the three characteristic dark spots on the body. Slightly plumper and larger (2.5 cm / 1 inch) than the very slender B. brigittae.
Social Behavior: Obligatory schooling fish. Creates cohesive groups (recommended from 15 specimens up) that swim elegantly in shaded areas. Totally harmless nature towards everything and everyone.
Coloration and Sexual Dimorphism: The body is tinted pinkish-red or soft orange. It has a prominent round spot behind the gill covers, one at the base of the anal fin and one at the base of the tail. Dominant males are distinctly redder and more slender than gravid females.
Soins, reproduction et cohabitation
Aquarium Setup: A 40 cm (16 inches) tank hosts a good school. Lighting should be shielded by a thick blanket of floating plants (e.g. Pistia, Salvinia). Greatly appreciates tannins released by alder cones and Indian almond leaves (Catappa).
Diet and Feeding: In nature it preys on zooplankton and microscopic worms. In captivity it accepts very fine crumbled flakes, but the staple food must be brine shrimp nauplii, copepods, daphnia and microworms.
Water Quality: It poorly tolerates hard and alkaline tap waters, which fade its colors and reduce life expectancy. Needs parameters tending to acidic (pH 5.0 - 6.5) and extreme cleanliness without having currents in the tank.
Compatibility and Cohabitation: See Boraras brigittae: safe cohabitation only with Neocaridina, peaceful snails, Pangio and Corydoras pygmaeus/hastatus. In a community aquarium with fish over 4 cm (1.5 inches) it would quickly be consumed or die of stress.
Aquarium Breeding: Scatters sticky eggs daily on tufts of Java moss or Riccia fluitans. If the school is well fed and the mosses are thick, it is possible to see slight increases in population without any intervention by the aquarist.
Risks and Diseases: Many wild populations (e.g. in Singapore) are now extinct due to the conversion of peatlands into cultivated land. Very sensitive to sudden changes in pH and, due to its size, a victim of filters without a protective sponge.
Origine et répartition géographiques
Widely distributed in Southeast Asia (Peninsular Thailand, East Malaysia, Singapore, Sumatra). Inhabits peat swamps (blackwater) and river inlets closely associated with the ancient pristine rainforest.
Origine
Asie du Sud et du Sud-Est
Profil de poisson
- Tempérament
- Territorial
- Boraras maculatus is an exceptionally peaceful, shy, and gentle species that poses no threat to any tankmates. They are shoaling fish that feel secure only when kept in a group of their own kind. While they are generally peaceful, dominant males may exhibit minor territorial displays during spawning periods, which are harmless and involve no physical injury. Because of their timid nature, they can easily become stressed if housed with larger or overly active species.
- Régime alimentaire
- Omnivore
- In the wild, Boraras maculatus is a micropredator feeding on small insects, worms, and micro-crustaceans. In the aquarium, they should be offered high-quality crushed flakes or micro-pellets as a staple. To ensure vibrant coloration and support overall health, their diet should be regularly supplemented with baby brine shrimp, Daphnia, or microworms. Due to their tiny mouths, all food items must be appropriately sized for easy ingestion.
- Espérance de vie
- 3-5 years
- Taille adulte
- 2.5 cm
- Ratio des sexes
- Group
- This species does not require a specific male-to-female ratio for general aquarium keeping, but they must be kept in a group. A minimum shoal of eight to ten individuals is recommended to promote natural schooling behavior and reduce stress. Keeping a larger group allows males to display their most intense coloration as they compete for female attention. In a group context, their social hierarchy is established without causing harm to any individuals.
- Fréquence d'alimentation
- 2-3 times daily
- Due to their very small body mass and high metabolic rate, Boraras maculatus benefits from being fed small portions two to three times daily. This feeding schedule prevents digestive issues while ensuring they receive enough energy to remain active. Care must be taken not to overfeed, as uneaten food will quickly degrade the water quality in a nano aquarium. Feeding only what they can consume within one to two minutes is the best practice.
- Charge biologique
- Low
- Boraras maculatus has an extremely low individual biological load due to its miniature size of about two centimeters. However, because they must be kept in large groups, their collective waste should be managed with stable filtration. A gentle sponge filter or an air-powered filter is highly recommended to prevent these tiny fish from being sucked into the intake. Regular partial water changes are essential to keep nitrate levels low and maintain pristine water quality.
- Courant
- Strong
- This species originates from slow-moving, quiet forest streams and peat swamps with minimal current. Consequently, they prefer weak water flow in the aquarium, as strong currents can easily exhaust and stress them. Filtration should be designed to keep water movement gentle, utilizing sponge filters or filter outlets directed against the glass. Creating areas of calm water with dense planting allows them to swim comfortably and exhibit natural behaviors.
- Risque de saut
- Yes
- Although Boraras maculatus is a very small fish, they are agile swimmers that can jump out of the aquarium when startled or stressed. A tight-fitting lid or cover glass is essential to prevent any tragic escapes from the tank. Floating plants can also help cover the water surface, making the fish feel secure and reducing their instinct to jump. Keeping the aquarium water level slightly below the rim provides an extra safety margin.
- Reproduction
- Oviparous
- Boraras maculatus is an egg-scattering species that exhibits no parental care, and they will readily consume their own eggs and fry. Breeding them is moderately challenging and is best accomplished in a dedicated, dimly lit breeding tank with soft, highly acidic water. The bottom of the breeding tank should be covered with spawning mops, Java moss, or a mesh grid to protect the eggs. After spawning occurs, the adult fish must be removed immediately to ensure the survival of the offspring.
- Compatibilité et compagnons
- Community
- Due to their tiny size and timid nature, Boraras maculatus is not suitable for standard community aquariums with larger, active fish. They are best kept in a species-only setup or with other peaceful micro-fishes such as small danios, dwarf rasboras, and tiny catfish. They are also excellent companions for freshwater dwarf shrimp, as they are too small to harm juvenile shrimp. Avoid housing them with any species large enough to view them as potential prey.
- Niveau dans le bac
- Top/Middle
- Boraras maculatus primarily occupies the middle and upper levels of the water column, where they actively swim in schools. They will frequently explore other areas of the tank, especially if dense vegetation is provided for cover. In a well-planted aquarium with floating plants, they are much more active and visible in the upper sections. Their presence in the middle-top zone makes them excellent companions for bottom-dwelling species like dwarf corydoras.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 3,3 ± 0,4 se
- Résilience
- Élevée (moins de 15 mois)
- Singularité phylogénétique (PD50)
- 0.5156
- Relation bayésienne longueur-poids
- a = 0.00891, b = 3.02
- VulnérabilitéVulnérabilité faible (10 / 100)
Galerie d'images
Images sous licence liées à l'espèce ou, lorsqu'elles sont indiquées, au taxon représentatif le plus proche.
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