The Scissortail Rasbora is a graceful schooling fish with a distinctive fork-tailed scissors motion, hardy and perfect for peaceful community tanks.
Overview
The Scissortail Rasbora (Rasbora trilineata), also known as the Three-lined Rasbora, is one of the most recognizable members of the genus Rasbora from the family Cyprinidae. In the wild, this species is widely distributed across freshwater habitats of Southeast Asia: rivers, streams, and flooded forests of Thailand, Malaysia, Sumatra, and Borneo. They form schools in the middle and upper water layers, preferring areas with moderate current and sparse vegetation.
The common name "Scissortail" comes from the distinctive movement of its caudal fin: while swimming, the deeply forked lobes with contrasting black-and-white markings rhythmically open and close, resembling a pair of working scissors. The body is sleek and elongated, silvery-olive in colour, with a fine dark stripe running from the gill cover to the base of the tail. The large scales have a subtle pearlescent sheen, especially noticeable under side lighting.
Adults reach 10-12 cm in length, making this one of the larger species within the genus. Lifespan in aquaria is 5-7 years with proper care. Sexual dimorphism is subtle: females are slightly plumper than males, especially during breeding season, while males tend to be more slender and slightly more vivid in coloration. Rasbora trilineata is an active, lively diurnal fish that truly comes alive when kept in a group of its own kind.
Tank Requirements
A comfortable home for a school of Scissortail Rasboras requires an aquarium of at least 100 litres. Given their activity level and size, bigger is always better: in tanks of 150-200 litres or more, the school looks truly spectacular and the fish behave more naturally.
Optimal water parameters are: temperature 24-28°C, pH 6.0-7.5, and general hardness GH 5-12. In the wild, Rasbora trilineata inhabits soft, slightly acidic water, so values in the lower half of these ranges are preferable, although the fish is quite adaptable.
When setting up the aquarium, it is essential to provide ample open swimming space — these rasboras are constantly on the move and need room to swim. Plant the perimeter with live plants (Vallisneria, Cryptocoryne, Echinodorus) to provide shelter and create a natural feel. A dark substrate will beautifully highlight the silvery coloration of the fish. Moderate flow from the filter is welcome, as rasboras enjoy swimming against the current.
Important: the aquarium must have a tightly fitting lid! Scissortail Rasboras are excellent jumpers, capable of leaping out of the water at the slightest fright. Even a small gap in the cover can result in the loss of a fish.
Feeding and Diet
In nature, Rasbora trilineata is an insectivorous and omnivorous fish, feeding on small invertebrates, insect larvae, zooplankton, and algal growths. In the aquarium, it has an excellent appetite and readily accepts virtually any food offered.
The staple diet can consist of high-quality flakes or small granules for tropical fish. However, to maintain health, activity, and vibrant coloration, it is important to regularly diversify the menu. Offer live or frozen foods: bloodworms, brine shrimp, daphnia, cyclops, and glassworms. Protein-rich supplements are especially valuable and noticeably invigorate the fish.
Feed twice daily in small portions that the fish consume within 2-3 minutes. Rasboras feed primarily in the middle and upper water layers, so flakes and slow-sinking granules work best. A weekly fasting day is beneficial for digestion and overall health.
Care and Maintenance
The Scissortail Rasbora is one of the most undemanding aquarium fish (care level 2 out of 5), making it an excellent choice for both beginners and experienced aquarists alike.
Perform weekly water changes of 20-25% using dechlorinated water with parameters close to those in the tank. A good filter — internal or external — will provide the necessary mechanical and biological filtration. Monitor ammonia and nitrite levels (should be 0) and nitrates (no more than 20-30 mg/l).
Regularly vacuum the substrate with a siphon to remove leftover food and organic debris. Test water parameters, especially after setting up a new tank or adding new inhabitants.
It bears repeating: a lid on the aquarium is mandatory. Rasboras easily jump out, particularly in stressful situations — sudden light changes, water changes, or being startled. Make sure all openings in the cover are sealed. With proper care, Rasbora trilineata lives 5-7 years, delighting its owner with its energy and grace.
Compatibility
The Scissortail Rasbora is an exceptionally peaceful fish (aggression level 1 out of 5), ideal for community aquariums. They should be kept in a school of at least 6 individuals, preferably 8-10. In smaller groups, the fish become timid, pale, and may display uncharacteristic nervousness.
Excellent tankmates include other peaceful species of comparable size. Among characins, great choices are Black Neon Tetra, Neon Tetra, Cardinal Tetra, and Flame Tetra. Among cyprinids, good companions include Harlequin Rasbora, Zebra Danio, and Cherry Barb. On the bottom level, various species of Corydoras make excellent tankmates.
Among labyrinth fish, Pearl Gourami and Dwarf Gourami are suitable, and among peaceful cichlids, German Blue Ram and Bolivian Ram work well.
Avoid housing them with large aggressive species or active fin-nippers. Do not keep Scissortail Rasboras with large cichlids or predatory fish that may view them as prey. Very small tankmates (dwarf rasboras, fry) are also inadvisable — a large rasbora may accidentally swallow them.
Breeding
Breeding Rasbora trilineata at home is moderately challenging (difficulty level 3 out of 5) and requires some preparation. These fish are typical egg scatterers that spread their eggs among plants and show no parental care.
Prepare a separate breeding tank of 30-50 litres with soft water (GH 3-6), pH 6.0-6.5, and a temperature of 26-28°C. Cover the bottom with fine-leaved plants — Java moss, Cabomba, or Hornwort — or use a spawning grid to protect the eggs from being eaten by the parents. Water level should be 15-20 cm. Keep lighting dim.
One to two weeks before spawning, select a pair or small group (2 males and 3-4 females) and feed them generously with live foods — bloodworms, brine shrimp, and daphnia. A female's readiness is indicated by a noticeably rounded belly. Triggers for spawning include a slight temperature increase of 1-2 degrees and a partial water change with softer water.
Spawning usually occurs in the morning hours. The fish scatter small, weakly adhesive eggs among the plants. After spawning, the parents must be removed immediately, as they will eat their own eggs. Darken the tank.
The eggs develop within 24-36 hours. Larvae feed on their yolk sac for the first few days, then begin free-swimming and feeding. First foods include infusoria, microworms, and liquid fry food. After 7-10 days, they can transition to baby brine shrimp. Maintain impeccable water quality with daily water changes of 10-15%. Fry grow at a moderate pace, reaching 2-3 cm by 3 months of age. The characteristic tail fin pattern develops by 2-3 months of age.