Red-Tailed Rasbora

Rasbora borapetensis

Also known as Blackline Rasbora

Animalia›Chordata›Cypriniformes›Cyprinidae

The Red-Tailed Rasbora is a small, elegant freshwater fish native to Southeast Asia, known for its distinctive red tail and silvery body. These peaceful schooling fish are ideal for planted community tanks and are relatively easy to care for, making them suitable for beginner to intermediate aquarists. They thrive in groups and display beautiful schooling behavior when kept in adequate numbers.

Where it's from

Native to the Ba, Bangpakong, Cai, Chantaburi and 10 other river basins

Vietnam, Thailand, Malaysia and Laos

Recorded as introduced in Singapore

At a glance

Size: 2 in; 5 cm
Min tank: 20 gal; 76 L
Group: 6+
Temp: 72–79°F; 22–26°C
pH: 6.0-7.0
GH: 36–143 ppm; 2–8 dGH
Temperament: Peaceful
Swims: Middle
Lifespan: 4-6 yrs

Ammonia 0 ppm and nitrate under 20 ppm.

Care

Diet

Red-Tailed Rasboras are omnivorous and should be fed a varied diet of high-quality flake foods, micro pellets, and small live or frozen foods such as daphnia and brine shrimp. Feed small amounts 2-3 times daily, providing only what they can consume in a few minutes. Occasional vegetable matter like blanched spinach can supplement their diet.

Behavior

These fish are active schoolers that display vibrant colors and engaging behavior when kept in groups of at least 6 individuals. They prefer the middle water column and are generally peaceful with other non-aggressive species. They are most active during dawn and dusk hours and appreciate planted tanks with plenty of hiding spots.

Breeding

Red-Tailed Rasboras are egg scatterers that breed readily in well-established, densely planted tanks with soft, acidic water. Breeding pairs should be conditioned with high-quality live foods before spawning. Fry are very small and require infusoria or liquid fry food initially, making breeding moderately challenging for beginners.

Tank mates

See all 5

Neon Tetra

Similar size and peaceful temperament, both prefer soft acidic water

excellent

Cardinal Tetra

Compatible water parameters and peaceful schooling behavior

excellent

Harlequin Rasbora

Same family, similar size and care requirements

excellent

Dwarf Gourami

Peaceful and compatible, though males can be territorial

good

Otocinclus

Peaceful algae eater that shares similar water parameters

excellent

Fits a 20-gallon tank Beginner-friendly Peaceful

No state or federal restrictions on record.

Not legal advice, and possibly incomplete or out of date. Rules vary by state and change over time; check with your state wildlife or agriculture agency before buying, keeping or shipping it.

The care information here is written with AI help, so it can contain mistakes. Spot one? Tell us and we'll fix it. Native range: Global Register of Introduced and Invasive Species (CC BY 4.0); Tedesco et al. 2017 (CC0).