Scissortail Rasbora
Rasbora trilineata
Min Tank Size
110L
Adult Size
10 cm
Lifespan
5 years
School Size
6+
About
Native to Southeast Asia, particularly the river systems of Thailand, Malaysia, Borneo, and Sumatra, the Scissortail Rasbora is one of the more striking schooling fish available to hobbyists. They get their name from that distinctive forked tail patterned in black and white, which flicks open and shut rhythmically as they swim, almost hypnotically. In motion, a tight school of these fish is genuinely impressive to watch.
They grow to around 9 centimeters in a home aquarium, making them noticeably larger than the typical rasbora. That size means they need real swimming space, and a tank shorter than 90 centimeters in length will feel cramped for an active school. They prefer soft to moderately hard water with a slightly acidic to neutral pH, but they're fairly adaptable and can handle a range of conditions as long as extremes are avoided. Temperature should stay in the 22 to 28 degree range.
Diet is easy. They'll take quality dried flakes or pellets without hesitation, and supplementing with frozen or live foods like daphnia, bloodworm, or brine shrimp keeps their color sharp and condition good. They're not fussy feeders and won't refuse much.
Behaviorally, these are about as easygoing as a fish gets. No aggression, no territory, no drama. They just want to swim fast with their school and have open water to do it in. A densely planted background with open midwater space suits them well.
If you want to see how other people are setting up tanks around this species, there are some genuinely creative builds worth browsing through.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Scissortail Rasbora together
Scissortail Rasbora are shoaling fish and need company of their own kind. Keep a group of at least 6. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
These fish get along with almost everything that won't eat them. Good choices include other peaceful mid-water schoolers like danios, other rasboras, and larger tetras. Bottom dwellers like corydoras and loaches work well since they occupy completely different zones. Gouramis are a common and successful pairing, as are angelfish in larger tanks, though keep in mind that very small shrimp like neocaridina juveniles may get picked off. Avoid housing them with anything small enough to be eaten or anything with a reputation for fin nipping, since while the scissortails themselves are tough, keeping stress low always helps schooling behavior.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest mistake beginners make is underestimating the tank length requirement. These are fast, active swimmers and a standard 80-liter cube or short tank won't give them what they need even if the volume looks sufficient on paper. A lid is non-negotiable since they will jump, especially if startled. Keeping them in groups of fewer than six tends to produce skittish, stressed fish that hide and lose color. Feed varied foods rather than relying on flake alone, and provide moderate flow to mimic their natural river habitat.
Behavior & Aggression
Scissortail Rasboras are consistently peaceful with no meaningful aggression toward other fish. They don't nip fins, don't guard territories, and don't show any bullying behavior even within their own school. Conspecific interactions are essentially neutral, with the school moving as a loose collective rather than establishing any hierarchy. The only caveat worth mentioning is that like most mid-sized fish, they may opportunistically eat very small invertebrates or fry they encounter, but this isn't predatory behavior in any deliberate sense.
Things to Know
- Needs a long tank for swimming, length matters more than volume
- Jumpers, a tight-fitting lid is necessary
- Small shrimp and fry may be eaten, adults are safer
- Can reach a surprising 12 cm, plan accordingly.
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