Blackline Rasbora

The Blackline Rasbora, also known as the Red-Tailed Rasbora, is a beautiful and active species native to Southeast Asian waterways. These fish feature a striking black lateral stripe running from head to tail, contrasted by a brilliant red or orange tail fin that creates a stunning visual effect when they swim in schools. Their silvery body reflects light beautifully, and their constant movement brings energy to any community aquarium. Blackline Rasboras are slightly larger than some of their smaller cousins like chili rasboras, making them more visible and impactful in the aquarium. They are hardy, adaptable fish that tolerate a range of water conditions and are peaceful community dwellers. When kept in groups of 6 or more, they display fascinating schooling behaviors and their red tails create flashes of color as they move through the water. Their combination of hardiness, beauty, and peaceful nature makes them an excellent choice for both beginners and experienced aquarists.

Care Requirements

Tank Setup

Blackline Rasboras thrive in planted aquariums of 20-30 gallons with open swimming areas. They appreciate plants for security but need space to display their active swimming behaviors. Use a darker substrate to make their colors pop. Provide moderate water flow to mimic their natural stream habitats. Gentle to moderate filtration is ideal.

Water Quality

• Temperature: 72-79°F (22-26°C)
• pH: 6.0-7.5
• Water Hardness: Soft to moderate, 2-15 dGH
• Ammonia/Nitrite: 0 ppm
• Nitrate: <20 ppm

Feeding

These omnivores readily accept flake foods, small pellets, and frozen or live foods. They eagerly come to the surface at feeding time. Supplement their diet with bloodworms, brine shrimp, and daphnia to enhance their coloration. Feed small amounts 2-3 times daily.

Behavior & Compatibility

Blackline Rasboras are peaceful schooling fish that should be kept in groups of 6 or more. They are excellent community fish that coexist well with other peaceful species of similar size. Their active swimming in the middle water levels adds movement to community tanks without causing stress to slower tank mates.

Tips for Success

• Keep in schools of 6-8 for best schooling behavior and color display
• Their red tails are most vibrant when kept in optimal water conditions
• Hardy and adaptable; suitable for beginners
• Active swimmers that need open space but appreciate plant cover
• May jump; ensure the tank has a secure lid
• Regular water changes help maintain their brilliant coloration