Emerald Eye Rasbora (Rasbora Brevibora)

A flash of emerald in the eye, betraying the shoal before it moves.

The Emerald Eye Rasbora is a peaceful nano schooling fish for planted tanks. Its emerald eye and tight shoals add vibrant life to any community aquarium.

• Water conditions: The Emerald Eye Rasbora (Brevibora dorsiocellata, formerly Rasbora dorsiocellata) thrives in stable, soft-to-moderately-hard water with a pH of 6.0–7.5, a temperature of 22–26°C (72–79°F), and a general hardness of 2–12 dGH. It is best kept in a mature, well-filtered aquarium with low nitrate levels and gentle to moderate water flow. These fish come from blackwater habitats, so the addition of Indian almond leaves, driftwood, or other botanicals to release tannins is beneficial and helps replicate their natural environment. Keep lighting subdued to moderate, as bright light can make them nervous. A tank of at least 45–60 cm (10–15 US gallons) is recommended for a group of 8–10 individuals. Avoid newly cycled aquariums; this species is sensitive to ammonia, nitrite, and sudden parameter swings. Acclimatise slowly using the drip method, and never pour shop water into your tank.
• Suitable tank mates: Because Emerald Eye Rasboras are small, peaceful, and somewhat timid, they do best with other calm nano species that will not outcompete or harass them. Ideal tank mates include neon and cardinal tetras, ember tetras, chili and harlequin rasboras, pygmy corydoras, kuhli loaches, sparkling gouramis, honey gouramis, and peaceful livebearers such as endlers. They also work well in shrimp and snail communities, including Neocaridina and Caridina shrimp. Avoid large or boisterous fish, fin nippers such as tiger barbs, and any species large enough to eat them, including angelfish, large cichlids, and goldfish. Keep them in a shoal of at least 8–10; a larger group of 12–15 is even better, as it reduces stress, encourages natural schooling behaviour, and makes the fish more visible and colourful. These rasboras also make excellent dither fish for shy species.
• Feeding habits: Emerald Eye Rasboras are micropredators with small stomachs and should be fed small portions two to three times daily. They readily accept live and frozen foods such as daphnia, cyclops, moina, baby brine shrimp, micro worms, and grindal worms, which should form the backbone of their diet for optimal condition and colour. They will also take high-quality micro pellets, crushed flakes, and powdered foods, but dry foods should be very fine. Feed only what the fish can consume within one to two minutes, and remove any uneaten food to avoid fouling the water. Because they are mid-water to surface feeders, ensure food is distributed where they can reach it, especially in a community tank with more assertive species. A varied diet rich in live or frozen fare supports the health of their emerald eye spot and helps condition them for spawning.
• Care requirements: Adult Emerald Eye Rasboras typically reach 3–4 cm (1.2–1.6 in), making them an excellent nano aquarium choice. Provide a densely planted tank with floating plants, moss, driftwood, and leaf litter to create shaded areas and broken lines of sight. A dark substrate and dim lighting will bring out their best colours and make them feel secure. These fish are known jumpers, so a tight-fitting lid is essential. Perform weekly water changes of 20–30%, siphon the substrate, and rinse filter media in tank water only. Avoid large, sudden changes in temperature or chemistry; stability is far more important than chasing exact numbers. Quarantine new arrivals before adding them to the main tank, and monitor for signs of stress such as clamped fins or faded colour. Breeding is possible in soft, acidic water; they are egg scatterers and will spawn among moss or spawning mops, though raising the fry requires tiny live foods. Overall, this is a rewarding species for the careful aquarist who values peaceful, active shoaling behaviour.