Dwarf Rasbora Care Guide - Aquarium Setup, Diet & Breeding

The Dwarf Rasbora, Boraras maculatus, is a tiny, delicate cyprinid with a warm reddish-orange body and distinctive dark markings along its sides. Its small size and lively shoaling behaviour make it one of the most appealing inhabitants for a carefully planned nano aquarium.

Several dark spots interrupt the body colour, including a prominent marking toward the middle of the flank and darker areas near the front and rear of the body. Colour intensity varies with mood, condition and surroundings, with healthy males often displaying especially rich red tones.

In the wild, these rasboras inhabit quiet, shallow waters beneath the forest canopy. Fallen leaves, submerged roots and aquatic vegetation create a complex habitat where the fish can shelter and forage among tannins and gentle currents.

Dwarf Rasboras are peaceful but naturally cautious, and they are most confident when kept in a proper shoal. In a settled group they spend much of their time weaving through plants and displaying to one another, producing constant but subtle movement rather than frantic activity.

Dwarf Rasboras are native to Southeast Asia, particularly the Malay Peninsula and parts of Sumatra. They occur in slow-moving, tannin-stained forest streams, peat swamps and shallow blackwater habitats surrounded by dense vegetation.

A group should have at least 40 litres, with a footprint of about 60 by 30 cm preferred because length is more useful than height for active shoaling. Use gentle filtration and subdued flow, with dense planting, fine-leaved plants, moss, floating cover, roots and some leaf litter to provide shelter and recreate their forest-stream habitat. A dark, fine-grained sand or smooth substrate helps the fish feel secure and shows off their colours, while subdued lighting and tannin-rich decor are especially suitable.

Up to about 2.5 cm (1 inch) in total length. Females are generally slightly larger and deeper-bodied than males, while males tend to remain slimmer.

Offer a varied diet of high-quality crushed flakes, fine micro-pellets and suitably sized granules. Supplement this with small live or frozen foods such as baby brine shrimp, daphnia and cyclops to encourage strong colour and good condition. Feed only tiny portions that the group can consume quickly, as their small mouths and low waste tolerance make overfeeding particularly problematic.

Dwarf Rasboras are best suited to peaceful nano communities. Suitable companions include small Corydoras species such as Pygmy Corydoras, other Boraras, small non-aggressive rasboras, Otocinclus and peaceful freshwater shrimp, provided the shrimp setup is appropriate. Avoid angelfish, larger gouramis, most larger barbs, aggressive fish and any tankmate large enough to swallow these tiny rasboras or intimidate them into hiding.

Dwarf Rasboras are continuous egg scatterers that may spawn among fine-leaved plants or moss when given mature, stable, soft and slightly acidic water. For reliable breeding, place a conditioned group in a separate, dimly lit spawning aquarium with plenty of moss or a spawning mop. They release a few adhesive eggs at a time, but adults may eat them, so remove the adults or protect the eggs with a mesh barrier. The fry are tiny and should initially be fed infusoria or another suitably small liquid fry food before progressing to newly hatched brine shrimp.

Females are usually a little larger, rounder and less intensely coloured, particularly when carrying eggs. Males are slimmer and often develop stronger red or orange coloration, with more noticeable colour during courtship.