Dwarf Spotted Rasbora (B. maculatus)

Boraras maculatus, commonly known as the dwarf spotted rasbora, is a tiny Southeast Asian cyprinid native to Borneo, where it inhabits peat swamp forests and blackwater streams. These environments are slow-moving to nearly stagnant, heavily shaded by dense forest canopy, and filled with leaf litter, fallen branches, and organic debris. The water is typically tea-colored, very soft, highly acidic, and extremely low in dissolved minerals, creating dim conditions with minimal current.

Adult Boraras maculatus is very small, usually reaching about 0.75 to 1 inch in length. The body is slender and translucent with a warm reddish to pinkish hue, marked by several distinct dark spots along the flank and near the caudal peduncle. In good conditions, males develop deeper red coloration, while females appear slightly fuller-bodied and paler. Despite their minute size, the contrast between the red body and dark spotting makes them visually striking in softly lit aquariums.

A tank of at least 10 gallons is suitable for a proper group, though larger volumes provide greater stability and better long-term success. Boraras maculatus is a schooling species and should be kept in groups of ten or more to reduce stress and encourage natural behavior. The aquarium should be heavily planted or structured with leaf litter, fine branches, and floating plants to diffuse light and create a shaded, enclosed environment. Open swimming space should still be maintained through the midwater, but overall lighting should remain subdued.

Water conditions are critical to maintaining health and coloration. Boraras maculatus requires very soft, acidic water, ideally with a pH below 6.0 and minimal hardness. Temperatures between 74 and 80 degrees Fahrenheit are appropriate. Stability is essential, as this species reacts poorly to rapid changes in water chemistry. The use of botanicals such as leaf litter, seed pods, and natural wood helps maintain suitable blackwater conditions and supports natural behavior.

Feeding Boraras maculatus requires very small, appropriately sized foods. In nature they feed on tiny insects, microcrustaceans, and other minute organisms suspended in the water column. In the aquarium they accept finely crushed flakes, micro-pellets, and frozen foods such as baby brine shrimp, cyclops, and daphnia. Food particle size is especially important due to their extremely small mouths.

Temperament is peaceful, shy, and non-aggressive. Boraras maculatus should only be kept with other very small, gentle species that tolerate similar blackwater conditions. Suitable tankmates include other Boraras species, Sundadanio, and delicate blackwater-adapted fish. Larger or more active fish will stress them and interfere with feeding.

Breeding is possible in captivity but challenging and usually occurs only in very soft, acidic water under low-light conditions. Eggs are scattered among fine plants or leaf litter, and adults do not provide parental care. Eggs and fry must be protected if breeding is desired.

Boraras maculatus is a delicate, jewel-like schooling fish best suited for dedicated blackwater aquariums. Its tiny size, subtle red coloration, and calm behavior make it an excellent choice for aquarists who can provide stable, soft, acidic water and a quiet, naturalistic environment.