Spotted Rasbora

The Spotted Rasbora (Boraras maculatus) is a diminutive and endearing micro fish native to slow-moving, heavily vegetated peat swamp streams and forest pools in Peninsular Malaysia and Sumatra. Reaching only about 2.5 cm in length, it has a semi-translucent pinkish to reddish body adorned with a series of bold black spots along the flank, giving it a uniquely spotted appearance among the Boraras genus. It closely resembles Boraras brigittae but is distinguished by its spotted rather than stripe-and-spot patterning. In the wild, it inhabits the same type of tannin-stained, soft, and acidic blackwater habitat typical of the Boraras family. These conditions should be replicated in the aquarium with soft water, low pH, dim lighting, and a natural leaf litter or dark substrate. A heavily planted nano aquarium with Indian almond leaves and driftwood creates an ideal biotope. As with other micro rasboras, the Spotted Rasbora should be kept in groups of at least eight for comfort and natural behavior. Larger groups of twelve or more produce a lively, shimmering mass of color and movement. It is fully compatible with dwarf shrimp such as Neocaridina and Caridina, making it one of the few fish suitable for a shrimp-focused aquarium. It will not harm adult shrimp or larger juveniles. Diet consists of micro-sized foods including baby brine shrimp, micro worms, daphnia, and crushed flake or micro-pellets.

Tank Setup: A nano aquarium of at least 20 liters is sufficient for a small group of eight. Larger tanks of 30–40 liters allow for bigger groups and more dynamic schooling. Use a dark substrate, driftwood, and Indian almond leaves to recreate a blackwater aesthetic. Dense plantings of Java moss, Bucephalandra, and small crypts provide shelter and enrichment.

Water Parameters: Soft, acidic water is essential. Target pH 4.5–7.0, GH 0–8, KH 0–4, and temperature 22–28°C. Use RO or soft tap water. Peat filtration or blackwater extracts help achieve and stabilize the correct water chemistry. Avoid hard alkaline water, which can stress and shorten the lifespan of this species.

Filtration: A sponge filter is ideal, providing gentle mechanical and biological filtration without creating excessive current. The Spotted Rasbora is not adapted to strong flow.

Feeding: Offer micro-pellets, baby brine shrimp, micro worms, daphnia, and Grindal worms. Their small mouths require appropriately sized food particles. Feed twice daily in small amounts.

Social Behavior: Keep in groups of at least 8, ideally 12 or more. Suitable tankmates include other Boraras species, pygmy corydoras, and dwarf shrimp. Avoid any fish large enough to consume them.

Health: Sensitive to hard water and chemical additives. Avoid using any medications containing copper in tanks with these fish. Quarantine new additions carefully before introducing them to the main tank.