Firefly Rasbora

Boraras urophthalmoides

The Firefly Rasbora (Boraras urophthalmoides) is a miniature freshwater fish from the carp family, native to Southeast Asian waters. It is characterized by small size (usually 2–2.5 cm), an elegant elongated body, and distinctive coloration: a reddish-orange stripe runs along the side, and a dark spot at the base of the tail fin resembles an 'eye'. Thanks to its modest size and peaceful nature, this rasbora is ideal for nano aquariums and species-specific tanks with delicate plants. Schooling fish — it is best kept in groups of 8–10 or more: this reveals natural behavior and enhances coloration. The rasbora prefers soft, slightly acidic water (pH 6.0–7.0, GH 1–10) and a temperature of 22–26°C; maintaining stable parameters and avoiding sudden changes is important. In a school, the fish behave calmly, do not disturb plants, and coexist well with other small peaceful species — for example, microrasboras, shrimps, or small catfish.

Minimum aquarium volume40–80 Lallowed 20–200 L

Social modelGroup

Water temperature23–27 °Callowed 20–28 °C

pH6–7allowed 5.5–7.2

General hardness1–10 °dGHallowed 1–12 °dGH

Primary swimming zoneMid

Real specimens