Scissortail Rasbora Size: How Big Do They Get and How To Care for Them

Species Snapshot

• Species Name: Rasbora trilineata
• Common Names: Scissortail rasbora, three-lined rasbora
• Size: Up to 3.5 inches
• Lifespan: 3-5 years
• Native Distribution: Southeast Asia

Hailing from Southeast Asia, rasboras are small, active fish that exhibit an array of striking colors and eye-catching patterns. There are over 80 species in the genus Rasbora but a few stand out as mainstays in the aquarium hobby. One is the scissortail rasbora (Rasbora trilineata), named for its forked, scissor-like tail.

Scissortail rasboras are peaceful community fish that are relatively easy to keep (and breed) in the home aquarium. Here’s what you need to know about this species and how to care for them properly.

What Do They Look Like?

Like many rasbora species, scissortail rasboras are slim, streamlined fish. Their bodies are almost transparent except for a black line that runs horizontally along the length of the fish starting behind the gills and extending through the tail. Iridescent scales make this species shimmer and sparkle under the right lighting.

This species’ tail is deeply forked which is what gives it a scissor-like appearance. Each fork of the tail is colored with three bands of color—one yellow, one black, and one white. It’s this characteristic that gives the scissortail rasbora its other popular nickname, the three-lined rasbora.

How Big Do They Get?

Rasboras are generally small fish with most species growing to a maximum of 4 inches in length. The scissortail rasbora size is no exception, reaching an adult size of around 3.5 inches. Male scissortails tend to be slightly smaller and slimmer than females, but this species does not exhibit strong sexual dimorphism outside of breeding season.

Scissortail Rasbora Care Guide

Because they’re hardy, mild-tempered, and widely available as tank-bred specimens, scissortail rasboras are popular in the freshwater aquarium trade. They’re a top-dwelling species which makes them a great fit for community tanks stocked with mid-dwelling fish and bottom feeders. The key is to keep them in schools with at least six of their own species. Let’s dive into the details of scissortail rasbora care.

Tank Size and Décor

While scissortail rasboras remain fairly small, they are active fish that need plenty of open swimming space. A minimum tank volume of 20 gallons is recommended for a small group, and long aquariums are better than tall ones. If you plan to keep other fish with your scissortail rasboras, be sure to size up your tank accordingly.

Scissortail rasboras aren’t picky about tank setup and décor as long as they have room to swim. If you want to mimic the species’ native habitat, however, go for planted tank with subdued lighting and decorate with driftwood and rocks of varying size. Scissortail rasboras also appreciate a moderate degree of flow, so choose a filter accordingly or add a powerhead to create some current.

In the wild, scissortail rasboras can be found in quickly flowing streams as well as slower moving blackwater bodies. Feel free to add peat or another blackwater additive to your filter system but know that it’s not a requirement. One non-negotiable thing, however, is a tight-fitting lid because this species is prone to jumping.

Water Parameters

Most scissortail rasboras available in the aquarium trade are tank-bred instead of wild-caught, so they’re fairly adaptable to various environments. It’s wise, however, to recreate the water parameters of the tank they came from when setting up a tank of your own. Slow acclimation is recommended to avoid shocking or stressing your new fish.

In terms of water chemistry, scissortail rasboras prefer neutral to slightly acidic tank water with a pH level between 6.5 and 7.5. Scissortail rasboras generally prefer water that’s on the softer side as well, between 2 and 12 dGH. Water temperature should be kept stable somewhere in the 72°F to 78°F range.

Feeding Tips

Scissortail rasboras are omnivores and tank-bred specimens generally accept a wide range of commercial foods. A staple diet of nutritionally balanced flakes, pellets, or granules is acceptable but a diet consisting of small live, frozen, and freeze-dried foods will encourage the strongest coloration. The key is to choose foods small enough to fit in the rasbora’s mouth and to offer limited amounts at a time.

Tank Mates

With their mild temperaments, scissortail rasboras do well in most community tanks. They get along particularly well with other cyprinids, including other rasboras, as well as livebearers, small tetras, and bottom-feeders like loaches and catfish.

The best way to choose tankmates for scissortail rasboras is to select species that have similar tank requirements. And remember, this species needs to be kept in schools with at least six of its own kind. Scissortails can generally be mixed with other rasboras but make sure there are at least six of each kind.

Breeding Scissortail Rasboras

Scissortail rasboras are generally fairly easy to breed and may do so with little intervention in a well-maintained tank when fed a proper diet. This is an egg-scattering species and adults do not exhibit any parental care. If you hope to raise scissortail rasbora fry to maturity, you’ll need to set up a separate breeding tank or provide accommodations for the fry to hide until they grow big enough to avoid predation.

To encourage breeding, condition your scissortail rasboras with a diet of rich live foods like daphnia, brine shrimp, and bloodworms. When the females become rounded with eggs, separate several pairs into the prepared breeding tank. Adding small amounts of cool water to the tank throughout the day can help encourage spawning. Be sure to provide some kind of spawning medium like Java moss or a spawning mop.

Once your scissortail rasboras deposit their eggs, it’s best to remove the adults from the tank. Keep the lighting in the tank minimum to avoid fungus growth and perform frequent water changes to maintain high water quality. The eggs will hatch after about 24 hours and become free-swimming after another 48-72 hours. Raise the fry on very small live or frozen foods like baby brine shrimp until they’re large enough to be transferred to the community tank.