Phoenix Rasbora

Hailing from the blackwater streams and swamps of Borneo, specifically Kalimantan in Indonesia, Boraras merah is one of the smallest fish you'll ever keep in a home aquarium. Adults rarely exceed 1.5cm, making them true micro fish in every sense. They display a vivid red-orange body broken up by a bold dark lateral blotch and additional dark markings near the tail, which is what sets them apart from the closely related chili rasbora (B. brigittae). In good water and under proper lighting, a school of these fish looks like scattered embers drifting through the plants.

They belong in soft, acidic water, ideally pH between 4.5 and 6.5 with very low hardness. Blackwater setups with botanicals, driftwood, and tannin-stained water suit them perfectly and really bring out their coloration. They won't thrive long-term in typical hard tap water, so a reverse osmosis setup or access to naturally soft water matters here. Temperature should stay in the 24 to 27 degree range for best results.

Feeding is where beginners sometimes stumble. Their mouths are tiny, and most standard fish foods are simply too large. Micro pellets, baby brine shrimp, daphnia, and micro worms are the staples. They're active hunters for their size and will pick at anything appropriately small throughout the water column.

As a community fish they're absolutely docile, never harassing anything. The challenge is finding equally small and gentle tankmates rather than managing any aggression from the fish themselves. Browse builds tagged with phoenix rasbora to see how hobbyists set up blackwater biotopes and planted nano tanks around these little gems.