The Clown Rasbora, also known as rasbora kalochroma, is a species that is perfect for aquarium keepers ready to move up from guppies and other small fish into larger varieties.

It is not seen as often as other tropical species. Its sensitivity to changes in water quality makes it challenging to import and introduce to new surroundings.

The difficulty in establishing the species in your aquarium is made up for by their wonderful nature. Clown Rasbora are peaceful, colorful, and active. If you have not tried this underrated Asian species, you will find them a great addition to a community aquarium.

Keep reading to learn more about its proper care, tank requirements, and breeding information.

Clown Rasbora Stats

Listed tank sizes are the minimum

Size: Up to 3½ in (9 cm)
Tank: 30 gallons
Strata: Middle, top
pH: 5.5 – 7.0
Hardness: 2 – 10
Temperature: 76 to 84°F (24 – 29°C)
Order: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Rasbora

Origin and Appearance

The Clown Rasbora is a well-established schooling species native to Southeast Asia—from Malaysia, across the Sunda Islands in Borneo and Sumatra into Indonesia. Wherever you find dark water in these countries, you will see Clown Rasboras. They like slow-moving, warm water as found in streams, ditches, and ponds.

The bottom of their home waters is soft, mud-like mixes of twigs, decaying leaves, and branches from the forests above. The locations where you find them are often well vegetated with bottom rooted and floating plants.

The hallmarks of the species are a pinkish-red overall color with two large, dark blotches on their body, the smaller one behind the gill cover, and the second larger blotch on the midsection of the flank above the anal fin.

Variations include body colorings that are more orange and linear spots connecting the two main blotches. Clown Rasbora size can be up to three inches. The species will live for 3 to 5 years in well-kept aquariums.

Males and females are easily told apart. Male Clown Rasboras are slim and highly colored. Females of the species are more robust in body size and shape with subdued color.

They are peaceful fish and do well with tank mates that are about the same size. However, males will show some aggression to other males when courting females. This is indicated by darting behavior and vivid colorings on the males. Keeping them in mixed schools of 8 or more helps even out this behavior.

Clown Rasbora Care

Like tetra species, the Clown Rasbora comes from acidic, tannin-stained waters. The difference, which is important to keep in mind with this species, is that Clown Rasboras live in this water year-round and do not have the same level of heartiness with fluctuations of water chemistry.

They can be sensitive to increases in water hardness, decreases in acidity, and changes in water temperature. This makes them a species suited for aquarium keepers who want a biotope type of habitat for species that all do well in these unique water conditions.

The minimum size aquarium for keeping a school of 8 to 10 Clown Rasboras is 30 gallons. Horizontal format tanks are recommended. This is a species that likes its swimming room.

When startled, Clown Rasboras tend to leap. This trait necessitates a covered aquarium to keep them safe.

Larger tanks make it easy to add tank mates, plants, and décor to create a beautiful display. Additionally, they come with more complexity when it comes to fish care.

Maintaining stable water conditions is very important to this species. A good filtering system with an external canister is ideal. It will not clog with any debris from the substrate. A gentle water return is sufficient.

Maintaining water quality is the most important aspect of Clown Rasbora care. Letting water pH or hardness fall outside of the preferred range will cause the fish to weaken and die. Check water quality every few days and when something seems amiss in the aquarium.

Depending on your local climate, you will need an aquarium heater to help keep the water in the ideal temperature range of 76 to 84°F (24–29°C).

Adding Clown Rasbora to your aquarium can be tricky because they are easily shocked by changes in water quality. If you can, match the water quality of their transport water to that of your aquarium. One way to do this is to mix some destination tank water with the transport water and letting the fish acclimatize to it before adding them to the aquarium.

Standard aquarium sand is a good choice of substrate. Color is not important, although a dark substrate mimics their native environment. The substances you add to the tank will help form a dark substrate.

Clown Rasboras thrive in peat-stained water, so adding peat bags or other peat supplements will help them do well. Some aquarium keepers will add aquarium-safe peat directly to the tank. Once it is waterlogged, the peat will sink to the bottom and biodegrade.

Dried leaves from trees such as beech or oak can also be added as part of the substrate. As they biodegrade, it creates microbes that provide a food source for Clown Rasbora fry.

Keeping them in stained water also helps bring out their best colors. If you skip this aspect of their care, you will end up with fish that are muted and monotone in color. Bright rasboras are happy rasboras.

When setting up the aquarium, put plants at the back and sides to give your Clown Rasboras plenty of swimming room. Good choices are species such as guppy grass, both rooted and floating. Using floating plants will help curb the leaping tendency.

The species also like thickly matted plants like Java moss. Thick plants are important because it provides both food and shelter for Clown Rasbora fry.

Adding bottom structure like beach or oak driftwood sections will help recreate the look of their native habitat and supports the tannic nature of the aquarium water. Rocks and other structures can be added to support tank mates who need some shelter to be happy.

Tank Mates

Clown Rasboras are ideal tank mates for any species that does well in warm water or dark, tannic waters. A mix of schooling and bottom-dwelling species will make a great companion tank.

A few good tank mate candidates include:

  • Celestial Pearl Danio: The Celestial Pearl Danio has been popular in the aquarium world since the early 2000’s when they were first bred in captivity. They are bright, colorful tank mates with similar water preferences and tolerances.
  • Rosy Tetra: The Rosy Tetra, as well as many other species of Tetra, thrive in the same water conditions. They are peaceful but may engage in fin nipping when stressed or in overcrowded tanks.
  • Guppy: There are many varieties of guppy that make great tank mates. What they have in common is that they are peaceful, not too small, and get along well with everything that will not eat them. Some of the more ornamental varieties will look great in your aquarium.
  • Plecos: Plecos are beautiful little bottom-dwellers that are popular for their ability to help keep an aquarium clean. They are omnivores and will make short work of sinking food. They are peaceful but solitary. Don’t put more than one in standard size aquariums.
  • Corydoras: Like Plecos, Corydoras are a variety of bottom-feeding catfish commonly placed in tropical freshwater aquariums. They grow up to 4 inches in size and are peaceful omnivores.
  • Cardinal Tetra: Cardinal Tetras make great neighbors with many kinds of similarly gentle species. A small school of Cardinal Tetra adds beauty to any aquarium. Always a great choice. Add them in groups of 10.
  • Neon Tetra: Another great tank mate choice. Adding them in groups of 10, same as Cardinal Tetra, per 20-gallon tanks will give you an ever-moving, shimmering display.
  • Green Neon Tetra: If you want to keep a brightly colored aquarium, the Green Neon Tetra is a good tank mate to consider. Similar in size and appearance to the Neon Tetra, the Green Neon Tetra, as its name implies, has a beautiful streak of neon green along its sides.
  • Snails: Snails are slow and peaceful and will help keep the aquarium clean.


Clown Rasboras are continuous spawners and egg scatterers. They will breed readily when well-kept with no intervention on your part. If you have a lot of plants in the aquarium, do not be surprised to occasionally see small groups of fry hiding out in the branches.

It is relatively simple to differentiate males and females. Females are slightly bigger and more heavily built, and the males are slimmer and exhibit more vibrant colors. Having a mix of male and female Clown Rasboras in your aquarium will ensure yields of young fish.

Courtship can be identified by semi-aggressive, darting displays by males. They will encourage the females to lay their eggs on the bottom where the males fertilize them.

Clown Rasboras scatter their eggs over the bottom. Eggs hatch anywhere from 24 to 48 hours after being fertilized. They become self-sufficient in a few days.

Clown Rasboras are not parental and will eat their fry if the opportunity arises. If you can separate breeding fish into another tank then put them back in the home tank after the eggs have been fertilized, you will get the most survivability of the fry.

The young can be fed with infusoria or liquid fry food. In about a week, they should be large enough to baby brine shrimp or fine flakes.


Clown Rasboras are marvelously unfussy omnivores. They will dine happily on whatever you feed them.

A varied diet that leans toward protein foods will help them stay in their best colors. Good choices include:

  • Daphnia
  • Bloodworm
  • Earthworm
  • Dried flakes
  • Small pellets
  • Freeze-dried or live brine shrimp

Keep the diet varied, and you will have colorful, lively fish. Two small feedings a day are preferred over a single feeding and will help minimize the accumulation of food waste in the aquarium.


  • Clown Rasbora are sensitive to water quality and are not considered a beginner species.
  • They are dark water fish, so a means of keeping tannins in the water is important.
  • They are peaceful fish that do best in schools.
  • Tank mates can be any peaceful fish around three inches in size that thrive well in dark water.
  • Use dried leaves and similar matter over the sand to mimic their native substrate.
  • Mix rooted and floating plants to give their fry places to hide and feed.
  • Clown Rasbora are omnivores and will thrive on a varied diet.

While Clown Rasboras are not for beginners, they allow aquarium keepers to advance their skills and knowledge with a species that is more complicated to care for and maintain.

The rewards are large, colorful fish and a supply of new Clown Rasbora in a display setting that will make the colors of all fish in the aquarium vibrant and beautiful. Are you ready to add them to your tank?

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