--- type: species title: "Scissortail Rasbora Care Guide: The High-Energy Schooling Fish" slug: "scissortail-rasbora" category: "freshwater" scientificName: "Rasbora trilineata" subcategory: "Rasbora" lastUpdated: "2026-04-24" readingTime: 9 url: https://www.fishstores.org/species/scissortail-rasbora --- # Scissortail Rasbora Care Guide: The High-Energy Schooling Fish *Rasbora trilineata* Master Scissortail Rasbora care. Learn about Rasbora trilineata tank requirements, schooling behavior, and how to keep these active jumpers healthy. ## Species Overview Scissortail rasboras (*Rasbora trilineata*) are the larger, more athletic cousin of the rasboras most aquarists know from nano tanks. Adults push 4 to 5 inches in length, and their forked tail fin opens and closes like a pair of scissors as they swim — a hypnotic display that gives the species its common name. They are silvery-bronze, semi-translucent, and built like miniature torpedoes, with a horizontal black bar through each lobe of the tail that flashes against the body as they dart across the tank. This is not a nano fish. A school of scissortails belongs in a long, well-lidded community tank where they have room to sprint from one end to the other. Set them up properly and they become one of the most rewarding peaceful schooling fish in the freshwater hobby — hardy, adaptable, and a near-constant motion display in the upper-middle water column. | Field | Value | | ----------- | ---------------------------- | | Adult size | 3-4 in (7-10 cm), up to 5 in | | Lifespan | 5-7 years | | Min tank | 30 gallons (long format) | | Temperament | Peaceful, active schooler | | Difficulty | Beginner | | Diet | Omnivore | ### The "Three-Lined" Aesthetic: Identifying *Rasbora trilineata* The scientific name *trilineata* means "three-lined," and identification comes down to those lines. There is a faint dark lateral stripe running along the body from gill to caudal peduncle, and matching black bars on the upper and lower lobes of the deeply forked tail fin. Against the silver-bronze body, those tail bars are the diagnostic feature that separates scissortails from the dozens of other silver Southeast Asian cyprinids in the trade. Body color is otherwise understated — translucent silver with a faint olive sheen along the back, transitioning to white on the belly. They are not a "wow" fish at first glance in a store tank. The visual payoff comes from a school of 8-12 in motion, when the synchronized scissoring tails and silver flashes turn into a single coordinated display. ### Natural Habitat: River Basins of Southeast Asia *Rasbora trilineata* is native to the slow-flowing rivers, peat swamps, and forest streams of the Mekong and Chao Phraya river basins, with populations across Thailand, Cambodia, Laos, Vietnam, and Malaysia. In the wild they inhabit soft, slightly acidic, tannin-stained water with moderate current and dense bank vegetation. Unlike pure blackwater specialists, scissortails range across a wide variety of habitats — from clear forest streams to murkier lowland river edges — which is why they tolerate a much broader range of water chemistry than fish like chili rasboras. That adaptability is what makes them a bulletproof beginner schooling species. ### Adult Size and Lifespan Most aquarium-kept scissortails settle at 3 to 4 inches (7-10 cm) at maturity, with well-fed individuals in larger tanks reaching the full wild adult size of 5 inches. They are notably larger than the common rasboras most beginners encounter — roughly twice the length of a harlequin rasbora and six times the length of a chili rasbora. Lifespan in a stable, well-cycled tank is 5 to 7 years. They are not particularly fragile, and most premature deaths come from jumping out of uncovered tanks or stress from being kept in groups too small to feel secure. ## Water Parameters & Tank Requirements Scissortails are forgiving on water chemistry but demanding on tank shape. The single biggest mistake new keepers make is choosing a tall, narrow tank that gives the fish nowhere to run. ### Why Horizontal Swimming Space Matters (Minimum 30-40 Gallons) Scissortail rasboras swim. Constantly. They cruise the upper-middle water column at speeds that make most community fish look sluggish, and they do it in coordinated school formations that need linear distance to look natural. A "tall" 29-gallon tank with a 30-inch footprint feels cramped to a 4-inch fish that wants to dart 20 inches in a straight line and then turn around. A 30-gallon long (36 inches by 12 inches) or 40-gallon breeder (36 inches by 18 inches) is the practical minimum for a school of 6-8. A 55-gallon (48 inches long) is the sweet spot — that extra foot of horizontal room translates directly into more natural swimming behavior and brighter coloration. Think of footprint length as the controlling dimension, not gallonage. If you are setting up your first community tank around scissortails, see our [20-gallon fish tank guide](/guides/20-gallon-fish-tank) for context on why a standard 20-gallon high is undersized for this species — and what you gain by going to a 20-long or 30-long footprint instead. > **The scissor-action tail is synchronized with the school** > > When scissortails swim in a coordinated group, their forked tails open and close in near-unison as they brake, turn, and accelerate together. The "scissoring" motion is most visible when they move as a unit — solo or paired fish look listless, but a school of 8-plus in a long tank produces the signature synchronized display the species is named for. If you want to see this behavior, give them the school size and the horizontal runway they need. ### Ideal Parameters: Soft Acidic Water vs. Adaptability (pH 6.0-8.0) Scissortails do best in soft, slightly acidic water (pH 6.5-7.0, 4-8 dGH) that mirrors their native rivers, but they tolerate a remarkably wide range — anywhere from pH 6.0 up to 8.0, and hardness from 2 to 15 dGH. That tolerance is part of why they work as a community fish across most US tap-water profiles. If your water reads pH 7.6 and 10 dGH out of the tap, scissortails will be fine. Aim for stability over chasing perfect numbers. A consistent pH of 7.4 with weekly water changes does more for fish health than a wildly swinging 6.5 maintained with chemical buffers. Test ammonia and nitrite at zero before stocking, and keep nitrate below 30 ppm with weekly 25-30% water changes. ### Temperature Range (73-77°F) and Filtration Needs Target a temperature of 73-77°F (23-25°C). They handle the wider 72-82°F tropical range that most community fish tolerate, but the lower end of that band keeps their metabolism in a comfortable middle and reduces disease pressure. Filtration should provide moderate flow — these are mid-water swimmers that handle current well, unlike nano species that need still water. A canister filter or a quality hang-on-back rated for the actual tank size (not undersized "for the gallons" by the manufacturer) is appropriate. Surface agitation matters: scissortails are oxygen-hungry active swimmers, and a well-broken surface keeps dissolved oxygen high. ### The Importance of a Tight-Fitting Lid (The "Jumper" Factor) Scissortails are notorious jumpers. Any startle — a sudden room light, a tap on the glass, an aggressive tank mate, a change in current — can send them rocketing out of an open tank. Carpet-finds and behind-the-stand losses are the most common cause of premature death in this species. A tight-fitting glass lid or a custom mesh cover with no significant gaps is mandatory. Pay special attention to the cutouts for filter intakes and heater cords — those small openings are large enough for a 4-inch fish to squeeze through if it hits at full speed. If your tank has a rimless design with no built-in lid track, build a mesh lid frame; do not run scissortails open-top. ## Diet & Feeding Scissortail rasboras are unfussy omnivores. They will accept virtually any prepared food sized for their mouth, and feeding them is one of the easiest parts of their care. ### High-Protein Staples: Flakes and Micro-Pellets A high-quality tropical flake or sinking micro-pellet is the appropriate daily staple. Aim for a product with whole-fish or shrimp meal as the first ingredient — generic tetra flake works, but premium brands (New Life Spectrum, Bug Bites, Omega One, Hikari) produce noticeably better color and condition over time. Feed twice daily in small amounts that the school clears within 1-2 minutes. Scissortails feed at the surface and through the upper water column; uneaten food drifting to the substrate is wasted and pollutes the tank. If you have bottom-dwellers like corydoras, supplement with a sinking pellet for them rather than overfeeding the surface to compensate. ### Live and Frozen Treats: Daphnia, Artemia, and Bloodworms Two to three times per week, replace one feeding with a live or frozen protein treat. Frozen daphnia, brine shrimp (artemia), bloodworms, mysis shrimp, and blackworms are all excellent. The variety matters as much as the protein — scissortails fed on flake alone often fade in color and lose the silver sheen that makes a healthy school visually striking. Live foods trigger the most natural feeding behavior: a flake of frozen bloodworm dropped into a planted tank will set off a 30-second hunting frenzy as the school chases scattered pieces through the water column. This is good enrichment and it accelerates color and condition. ## Tank Mates & Compatibility Scissortails are model peaceful community fish — large enough not to be eaten by most mid-sized tank mates, small enough not to threaten anyone, and active enough to add motion to a tank without aggression. ### Schooling Dynamics: Why 6+ is the Absolute Minimum A school of 6 is the floor; 8-12 is the comfortable target. Below six fish, scissortails become visibly stressed — they hover in corners, lose color, and occasionally develop the fin-nipping behavior that the species is otherwise free of. > **Schooling 6+ is non-negotiable for behavior** > > Scissortails are obligate shoalers. A group of 3-4 fish will not display the synchronized swimming or signature tail motion the species is famous for, and individuals in undersized groups frequently develop stress symptoms — clamped fins, washed-out color, hiding behavior, and uncharacteristic nipping. Plan for 8 minimum, ideally 10-12, and choose tank size to match. Buying "a few to start" and adding more later usually means the first batch is permanently spooked by the time reinforcements arrive. ### Best Community Partners: Corydoras, Gouramis, and Tetras Scissortails pair beautifully with most peaceful community fish that occupy different parts of the water column. Corydoras catfish (any of the common species — bronze, peppered, panda) work the substrate while the rasboras patrol the middle and upper layers. Larger tetras (rummynose, lemon, black skirt), peaceful gouramis (honey, pearl, sparkling), and rainbowfish are solid mid-water companions. Other rasboras complement them well in larger tanks. A 55-gallon planted community with scissortails, [harlequin rasboras](/species/harlequin-rasbora) for color contrast, and a corydoras school below makes a textbook peaceful community setup. For tank-stocking ideas across the full freshwater spectrum, see our [freshwater fish guide](/guides/freshwater-fish). > **Active and fast — they need horizontal swimming room** > > Scissortails will physically dominate the upper water column with sheer activity. In a tank with slow-moving, long-finned fish — fancy guppies, bettas, angelfish, ornate male endlers — the constant rapid movement of a scissortail school can stress out the slower fish and make feeding difficult. Pair scissortails with similarly active, similarly sized companions, and reserve them for tanks with at least 36 inches of horizontal length so the school has room to move without crowding everything else. ### Species to Avoid: Large Cichlids and Slow-Moving Long-Finned Fish Avoid large cichlids of any kind — Oscars, Jack Dempseys, severums, even mid-sized firemouths can treat a 4-inch scissortail as a snack or a stress target. Skip aggressive barbs (tiger, rosy) that fin-nip, and avoid pairing with very slow, ornate fish like long-finned bettas, fancy guppies, or veiltail angelfish where the scissortail's speed creates a feeding-time mismatch. Goldfish are a temperature and chemistry mismatch — they belong in cooler, harder water and produce far more bioload than a tropical community can handle. Loaches in the clown loach family work as larger tank mates if your tank is genuinely big enough (75+ gallons) for both species at adult size. ## Breeding Scissortail Rasboras Scissortails are egg-scatterers and can be bred in the home aquarium with effort, though they are not as easy to spawn as some smaller rasboras. Most stock in the trade is commercially farmed in Southeast Asia. ### Distinguishing Males vs. Females Mature females are noticeably larger and rounder in the belly than males, especially when carrying eggs. Males stay more slender and develop slightly more vivid color along the lateral stripe and tail bars. The differences are subtle in juveniles — meaningful sexing is only reliable on fish over 2 inches. ### Setting Up a Spawning Mop and Soft Water Trigger A dedicated breeding tank of 10-15 gallons works best. Fill it with mature water at pH 6.0-6.5 and very soft hardness (under 4 dGH), use a sponge filter for gentle flow, and provide a thick mat of java moss or several spawning mops on the bottom. Lower the water depth to about 6 inches. Condition a small group (2-3 males, 4-5 females) for 7-10 days on heavy live foods — daphnia, baby brine, bloodworms — then move them to the breeding tank in the evening. Spawning typically happens at dawn the following morning, with eggs scattered into the moss or onto the substrate. Remove all adults immediately after spawning; they will eat the eggs. ### Raising Fry: Infusoria and Baby Brine Shrimp Eggs hatch in 24-30 hours, and fry become free-swimming at 4-5 days. Their first food is infusoria or commercial liquid fry food (Sera Micron, Hikari First Bites at smallest particle size); they are too small for newly hatched baby brine for the first 5-7 days. Once they can handle baby brine, they grow steadily, reaching 1 inch at about 6-8 weeks. The fry-rearing phase is the bottleneck for most hobbyists. If you do not have an active live-food culture, success rates drop sharply. Most home keepers enjoy watching adult spawning behavior and accept that fry survival without a dedicated rearing setup will be low. ## Common Health Issues Scissortail rasboras are robust and disease-resistant compared to many tropical species, but stress and water quality lapses still cause the standard freshwater problems. ### Stress-Induced Ich (White Spot Disease) Ich (*Ichthyophthirius multifiliis*) is the most common disease in newly purchased scissortails. It presents as small white spots resembling grains of salt on the body and fins. Outbreaks almost always trace to shipping stress, sudden temperature drops, or introduction of new fish from an untreated source. Treat by raising tank temperature gradually to 82°F over 24 hours and dosing an ich-specific medication at the labeled rate. Scissortails tolerate copper and malachite green at standard concentrations, but treat in the display tank only if no scaleless or sensitive species (loaches, corys) are present — otherwise move affected fish to a hospital tank. Read [how to acclimate fish](/guides/how-to-acclimate-fish) before introducing any new scissortails to your tank — proper drip acclimation over 45-60 minutes dramatically reduces post-purchase ich outbreaks. ### Bacterial Infections from Poor Water Quality Fin rot, cloudy eye, and "red sore" patches on the body are the most common bacterial issues, and they almost always trace to poor water quality. Test ammonia, nitrite, and nitrate first when symptoms appear. A 30-40% water change with parameter-matched water resolves most early-stage cases without medication. If a bacterial infection progresses past the early stage — visible ulcers, sloughing skin, severe fin damage — move the affected fish to a hospital tank and dose a broad-spectrum antibiotic (kanamycin, furan-2). Scissortails respond well to standard treatment if water quality is corrected at the same time. ## Where to Buy & What to Look For Scissortails are widely available in the freshwater trade. Most local fish stores with a community-fish section carry them, and they ship well from online vendors due to their hardiness. > **Buy Local** > > Always inspect scissortails in person before buying when possible. Look for active schooling behavior in the store tank, intact fins with no fraying, the characteristic black tail bars clearly visible, and an alert response when you approach. Avoid stores where the rasbora tank shows white spots, fish gasping at the surface, or one or more dead fish — the whole batch is at risk regardless of which individuals look healthy. ### Assessing Fin Health and "Scissoring" Tail Motion in Shops A healthy scissortail has fully extended, undamaged fins and an intact deeply forked tail. Watch the school for 30 seconds before buying — you should see the signature scissoring tail action as fish brake and turn, not stiff or clamped tail fins. Coloration should be a clean silver-bronze with crisp black bars on the tail; washed-out, gray, or faded fish are stressed or recently shipped. Avoid fish with cottony patches (fungal or bacterial infection), white spots (ich), or any fish hovering at the surface or in a corner away from the school. Ask the staff how long the fish have been in-store; ideally a week or more, with active feeding behavior. Buy at least 6, preferably 8-10, in one purchase — adding additional fish weeks later disrupts the established school dynamic. ## Quick Reference - **Adult size:** 3-4 in (7-10 cm), up to 5 in - **Lifespan:** 5-7 years - **Tank size:** 30 gallons minimum (36-inch long footprint), 40-55 gallons preferred - **School size:** 6 minimum, 8-12 ideal - **Temperature:** 73-77°F (23-25°C) - **pH:** 6.0-8.0 (optimal 6.5-7.0) - **Hardness:** 2-15 dGH (adaptable) - **Filtration:** Moderate flow, canister or HOB rated for the tank - **Lid:** Tight-fitting, mandatory — strong jumpers - **Diet:** Omnivore — flake, micro-pellets, frozen daphnia/brine/bloodworms - **Feeding:** 2x daily, small portions - **Best tank mates:** Corydoras, gouramis, larger tetras, [harlequin rasboras](/species/harlequin-rasbora), rainbowfish - **Avoid:** Large cichlids, fin-nipping barbs, slow long-finned fish, goldfish - **Difficulty:** Beginner — hardy and adaptable in adequately sized long tanks ## Frequently Asked Questions ### How big do Scissortail Rasboras get? Scissortail Rasboras are larger than many common rasboras, typically reaching 4 to 5 inches in length. Because of their size and active swimming nature, they require more open space than smaller relatives like the Neon Rasbora. ### Are Scissortail Rasboras fin nippers? Generally, no. They are peaceful community fish. However, if kept in too small a school (fewer than six), they may become stressed and display uncharacteristic nipping or skittishness toward tank mates. ### Do Scissortail Rasboras need a lid? Yes, a tight-fitting lid is mandatory. Scissortails are powerful swimmers and notorious jumpers, especially when startled or during nighttime activity. ### What is the best tank size for Scissortail Rasboras? While they can survive in a 20-gallon long, a 30-gallon or 40-gallon breeder is highly recommended. Their length and speed mean they need at least 36 inches of horizontal swimming room. ### Why is my Scissortail Rasbora losing color? Loss of color is usually a sign of stress, poor water quality (high nitrates), or a lack of dietary variety. Ensure your pH is stable and provide high-quality frozen foods to restore their silver sheen. --- *Source: [FishStores.org](https://www.fishstores.org/species/scissortail-rasbora)* *Last updated: April 24, 2026*