Yellow Polkadot Rasbora
Yellow Polkadot Rasbora (Boraras micros) is one of the most distinctively patterned nano fish in the hobby. The translucent golden-yellow body is scattered with three bold dark spots — one at mid-body, one near the dorsal fin, and one at the tail — giving this tiny fish the polkadot pattern its common name describes. At under 0.7 inches, it is among the smallest fish in regular aquarium keeping.
Feeding & Care Tip: Boraras micros has an exceptionally small mouth. Start juveniles on Sera Micron Nature and transition to Sera Vipan Baby flakes as they mature. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp. Feed small amounts 2–3 times daily.
Native to slow-moving and still blackwater habitats in northeastern Thailand, this species lives in extremely soft, acidic, tannin-stained water. Very soft slightly acidic water, dark substrate, tannin additions, gentle filtration, and diffused lighting through floating plants all contribute to best health and color.
Keep in groups of at least eight, preferably twelve or more. This fish is too small and timid for a typical community aquarium — best in a species-specific or nano setup with other very small, non-competitive species such as shrimp and other Boraras.
The Yellow Polkadot Rasbora is a genuine conversation piece — the three-spot pattern is unlike almost anything else in the freshwater hobby. In a blackwater nano aquascape, a school of these fish shimmers gold with flickering spots.
Care & Ideal Parameters
| Difficulty | Easy — Moderate |
| Temperament | Peaceful — Nano Species Only |
| Typical Adult Size | 0.65 inches (1.6 cm) |
| Min. Group Size | 8 minimum — groups of 12+ recommended for confidence and color |
| Ideal Temp | 68–79°F (20–26°C) |
| Ideal pH | 6.0–7.0 |
| Ideal GH | 1–4 dGH |
| Ideal KH | 0–2 dKH |
| Staple Food | Sera Micron Nature (juveniles); Sera Vipan Baby (adults) |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Northeastern Thailand |
| Notes | Extremely small — one of the tiniest aquarium fish. Sera Micron Nature for juveniles, Sera Vipan Baby for adults. Requires nano-only setup. |
