Scissortail Rasbora: Species Profile

Category: Barb

Common Names: Scissortail Rasbora, Silvertail, Scissor Tail Rasbora

Scientific Name: Rasbora trilineata

Family: Cyprinidae

Minimum Tank Size: 30 Gallons

Care Level: Moderate

Temperament: Peaceful

Max Size: 6 Inches

Temperature: 72-78 F

pH: 6.0-6.5

Tank Level: Middle to Top

Colors: Silver, Gold, Black

Diet: Omnivore

Breeding: Difficult

Scissortail Rasbora in Front of Plant

Scissortail Rasbora Species Overview

The scissortail rasbora is a beautiful fish with an incandescent body that shimmers in different lighting. When they swim, they will show off their attractive coloring.

Named for their forked tail, they are fast swimmers who enjoy being in community tanks with many varieties of fish.

Scissortail rasboras are perfect fishes for beginners because they are hardy and adaptable, and most importantly, they are easy to take care of and breed. They are active and lively fish that are great for freshwater aquariums. They are peaceful and docile and get along well with other non-aggressive fish.

Distinguishing Features

Scissortail rasboras have translucent bodies with a silver sheen. Depending on the lighting, the fish can give off subtle shimmers of other colors.

A thin horizontal line runs from its gill to its tail. The tail is forked with three bands of yellow, black, and white. The tail’s coloring is the reason why the fish is also called a three-lined rasbora.

The rasbora’s tail gives the fish its name. The tail is forked and can open and close, which looks like using a pair of scissors.

Rasboras belong to the freshwater Cyprinid family of minnows and carp. There are over 100 species of rasbora with variations in colors, markings, sizes, and body shapes.

Other than the scissortail, the most popular types of rasbora for home aquariums include:

  • Blackline rasbora
  • Chili rasbora
  • Brilliant rasbora
  • Porthole rasbora
  • Strawberry rasbora
  • Yellowtail rasbora
  • Clown rasbora
  • Phoenix rasbora
  • Dwarf of pygmy rasbora


With the scientific name Rasbora trilineata, the scissortail rasbora originally comes from the southern part of the Mekong River Basin, near Cambodia, Thailand, and Laos, as well as parts of Malaysia, Borneo, and Sumatra. Historically, the rasbora primarily inhabits slow-moving water bodies, such as swamps, but they can be found in fast-moving water, including lakes and streams.

The scissortail rasboras originate in freshwater. The fish thrive in forested or tropical areas. In tropical settings, their habitats consist of substrates of pebbles, large rocks and stones, sand, driftwood, and moss. The water is shallow and is typically unclouded and clear.

In forests, their habitats primarily include debris from trees (leaves, branches, twigs, and soil), boulders, and pebbles. The rasbora inhabits water that is often shadowed and darkened due to the tree canopy. The water is stained brown because of tannins and the decomposition of debris and materials from the forest.

The scissortail uses its speed to avoid larger predators. They feed on small insects in and on top of the water.

In the United States, scissortail rasboras do not come from the wild. They are entirely captive bred, making them ideal fish for the home aquarium.


The fish is long and slender with a torpedo-shaped body. The scissortail’s size allows it to maintain a high level of activity and to move quickly throughout the water.

The scissortail rasbora can grow to a maximum size of 6 to 8 inches. Most fishes sold are smaller and tend to be around 3.5 inches or 8 centimeters.

Mature male fishes tend to be smaller and slimmer than females. Adult females have rounder bellies and are typically larger.


With proper care and the right environment, the scissortail rasbora can live up to 5 to 7 years.


Gender differences between the scissortail rasbora are not easily identifiable or visible. Adult male scissortails are slimmer and smaller. During breeding and spawning, the male rasbora will exhibit darker colors.

Mature female rasboras tend to be larger, with a protruding belly. If you look down at your rasbora in their tank, you will be able to note the size differences between the male and female scissortail.

I, Lerdsuwa [CC-BY-SA-3.0]


The scissortail rasbora is a very peaceful fish. They are highly social and need the company of fellow scissortails. Because they are non-aggressive and social creatures, they do well in community tanks with other fish that are calm.

The scissortail is not aggressive and will avoid confrontations with its quick speed. There are no temperament differences between male and female rasboras.

Tank Parameters

Keeping your tank to a proper standard is essential when fishkeeping.

Minimum Tank Size

The scissortail’s tank should be a minimum of 30 gallons of water. Since scissortails should be kept as part of a school, a tank this size is needed to allow space for the entire group

Water Parameters

Make sure you are taking great care of the water in your tank. Failure to do so could result in the disease and the death of your fish.


The water temperature should be kept between 73 degrees and 78 degrees Fahrenheit (23 to 25 degrees Celsius). This can be a bit cooler than other tropical fish. If you keep scissortails with other tropical fish, make sure you find a temperature that works for every species. This usually means keeping the temperature at the upper end of their range – closer to 78 degrees F.


The scissortail prefers partially acidic water. Aim for a pH between 6.6 and 7.0.


The scissortail is a freshwater fish. The hardness of the water should be between 2 and 12 dGH.

Adding a tiny bit of aquarium salt can be added to help species overcome certain ailments and diseases. We’ll cover that in more detail below.

Tank Setup

Your tank is not only the home of your fish, it’s a decor piece in your home. Decorating it properly will enrich your fish and create an eye-catching piece.


For the substrate of your tank, you should choose a material like gravel, pebbles, or sand.


Scissortail rasboras need a lot of open space in their tanks because they are active and fast swimmers. You can provide different decorations in the tank, as long as they have the space to move around and swim freely. Scissortail rasboras, like many other fish, like lots of hiding spots. Decorations help provide them. This can go a long way towards helping to alleviate stress in your fish which will keep them healthier and happier.


For plants in the tank, you can mimic a riverbed or forest area that is native to the scissortail. Add plants like driftwood, java moss, rocks, and pebbles around the tank. Just like with decorations, plants can provide hiding places for your fish.


Because of the shimmers on their incandescent bodies, place lighting around the tank to bring out their colors. Make sure the lighting is subtle because they prefer low lighting.


Scissortail rasboras need clean and well-aerated water. Purchase a high-quality filter with a powerhead to introduce a strong water current so that they can stay active.


Use a heater as necessary to keep the water temperature between 73 degrees and 78 degrees Fahrenheit (23 to 25 degrees Celsius). Scissortail rasboras need stability in their tanks. Ensure that their water has minimal fluctuations.

Partially change their water out once every 2-3 weeks. Monitor the water and the tank setup regularly to ensure everything remains balanced.


Scissortail rasboras prefer live food like small insects but will eat more traditional fish food (either flakes or pellets).

Feed them a combination of a protein-rich diet and live foods, such as bloodworms and mosquito larvae. The food can be frozen or fresh.

The diet is key to a rasbora’s beautiful coloring, so feed the scissortail daily. Feed them small meals at least three times a day.


Scissortails are easy to breed. Their breeding is slightly more challenging than guppies, but it remains suited for beginners.

Breed mature scissortails in a separate tank. Scissortails will scatter their eggs, so add mesh or a spawning mat to collect eggs.

Ensure that the breeding tank has partially acidic water with a pH of 6.0 to 7.5. The water temperature should be 77 degrees to 82 degrees Fahrenheit.

Inject little quantities of colder water hourly to encourage spawning. Ensure that there is no direct lighting on the tank.

Continue to feed the scissortail a regular diet of live food, such as insects, mosquito larvae, and bloodworms.

Use a high-quality filter to ensure that the tank remains clean and healthy for the mature scissortail and the eggs.

After the eggs are released, move the mature scissortail back to their home tanks. The eggs will hatch on their own once they fully gestate, which is around 24 hours.

I, Lerdsuwa [CC-BY-SA-3.0]

Common Diseases

Scissortail rasboras are a hardy and adaptable species, but there are a few common diseases that rasboras can become infected with. The causes, symptoms, and treatments of the diseases include:

1) Fin rot and tail rot

Fin rot and tail rot are common diseases inflicted on fish in home aquariums. The diseases come from many different types of bacteria. Once the rasbora is infected, the bacteria will slowly eat away at its fin and tail.

Common causes of fin and tail rot are poor water quality, too many fish in one tank, a wound or injury to the fish, aggressive fish that bite fins or tails, and stress.

Once the scissortail gets infected, you will notice that the fin or tail becomes slightly discolored. As bacteria spread, it will begin to decay the fin or the tail, resulting in frayed or torn edges.

To treat your scissortail with fin or tail rot, immediately replace the water and monitor its temperature, pH, and salinity. Your vet may prescribe an antibiotic which you should drop in your tank daily.

Take care to avoid overfeeding and ensure that you place a scissortail with non-aggressive fish to avoid injuries.

2) Columnaris

Columnaris is another bacterial disease that commonly afflicts the scissortail rasbora. Found in freshwater tanks, the bacteria of columnaris often appears in home aquarium tanks. It can occur because of poor tank maintenance, such as substandard water quality, hot water temperatures, and poor diet.

Once the scissortail is infected with columnaris, it will show signs of white or bleached marks on the fish’s body. These patches can be hard to notice or identify at first, but they will continue to spread throughout the fish’s body and darken in color.

If left untreated, the bacteria will slowly kill the fish.

To treat columnaris, you will need an antibiotic from your veterinarian to destroy the bacteria.

You will also need to replace the water in your tank and perform regular aquarium maintenance. This upkeep includes monitoring your water quality and temperature and removing all debris and waste through filtration.

3) Dropsy

Dropsy is a symptom of an underlying disease in fish, such as from bacteria, parasites, or fungus. Dropsy is exacerbated by prolonged stressors, which leave the scissortail vulnerable to infections.

It is also worsened by environmental factors, such as poor tank maintenance.

Dropsy is characterized by a protruding and swollen belly. Fluids will accumulate in your scissortail’s abdomen at a rapid rate. After the stomach balloons, all other body parts will swell, damaging the internal organs and affecting the life expectancy of the fish.

If your scissortail rasbora has dropsy, get them to a veterinarian. The underlying cause of dropsy needs to be diagnosed for proper treatment. Likely, they will prescribe antibiotics for your fish.

Other treatments include replacing your water and regularly monitoring its temperature and pH. You can also add one tablespoon of salt to your tank’s water, but you need to ensure that the salinity will not harm the fish more.

4) Popeye disease

Popeye is a common disease for scissortail rasboras that affects their eyes. Popeye has a variety of causes, including a wound or injury, an infection, or substandard water quality.

When a scissortail becomes inflicted with popeye, its eyes will swell or bulge out of its sockets. The blood vessels around the eye can burst and the infection can spread throughout the fish.

If the infection is left untreated, your fish can lose an eye or have impaired vision for the rest of their life.

To treat popeye, determine the cause of the disease. If it is due to injury, it will likely heal on its own over time.

Examine your tank and remove any decorations or plants that caused the laceration. Remember that scissortails need open space in their tanks for their ample movement.

5) Saprolegnia

Saprolegnia is a disease that occurs in freshwater fish, making it a common illness of the scissortail rasbora. Saprolegnia is a result of bacteria or fungus in your fish’s aquarium.

When a scissortail lives in bad tank conditions or is already wounded or sick, the fish can become afflicted with saprolegnia.

Saprolegnia is characterized by white marks around the mouth of the scissortail. After the fish becomes infected, it can spread throughout the body, eventually causing death.

To treat saprolegnia, check your tank parameters and replace the lurking issues. The problem could be the water quality or temperature or removing debris with high-quality filtration. By fixing the tank conditions, you can eliminate the bacteria or fungus that has caused the saprolegnia.

Potential Tank Mates

Scissortail rasboras are highly social and like to be in schools of fish. Place them in a tank with at least 6 other scissortail rasboras.

Other species that are compatible tank mates with scissortails are:

  • Angelfish
  • Danios
  • Discus
  • Catfish
  • Guppies
  • Gourami

Scissortail rasboras thrive in community tanks with many non-aggressive and docile fish.