Cyprinids (Cyprinidae)

Clown Rasbora

Rasbora kalochroma

A member of the Cyprinidae family, the Clown Rasbora (scientific name Rasbora kalochroma) is characterized by its peaceful nature and relative ease of care, making it a good addition to a freshwater aquarium community.

Tank
from 250 L (66 gal)
Temperature
23 – 28 °C (73 – 82 °F)
Size in aquarium
10 cm (3.9 in)
Acidity
pH 5–7.5
Natural rangeRange on the map
  • Peninsular Malaysia area
  • Sumatra area
  • Indonesia
  • Malaysia
  • Singapore

Tank conditions

Plan the tank stocking
Temperature
23 – 28 °C (73 – 82 °F)
Water pH
Slightly acidic (5) – Neutral (7.5)
Water dH
Very soft (1) – Medium hardness (10)
Water salinity
no salt (freshwater)
Size in aquarium
10 cm (3.9 in)
Lifespan
4 years
Temperament
Peaceful (regular)
Toward small fish
not a predator
Required aquarium volume
from 250 L (66 gal)
Lighting
dimmed
Substrate
fine sand
Water flow
weak
Swimming level
middle level
Feeding
Any (universal)
Keeping
Group (8–10 individuals)
Jumping
high a tight-fitting lid is essential
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (group (8–10 individuals)), footprint, decor and tank mates.

Care and keeping

Description

Adults can reach a length of about 10 cm. Their coloration is predominantly red and orange, while the belly remains light. They have two large dark spots on their body, similar to those observed in the Elegant Rasbora. Young individuals, in turn, bear a resemblance to the Dwarf Rasbora. Such similarity often leads to confusion, where one species is supplied under the name of another. Sexual dimorphism is not pronounced; females are generally slightly larger than males.

Habitat

This species originates from Southeast Asia, specifically the peninsular part of Malaysia, as well as the islands of Sumatra and Kalimantan. These fish favor peat swamps located deep within tropical forests, and the streams and small rivers flowing nearby. Their natural habitat is characterized by shallow waters, with bottoms covered in fallen vegetation such as branches and leaves. The decomposition of organic matter causes the water to acquire a rich brown hue. Hydrochemical parameters in such conditions show extremely low pH and dGH values.

Behavior and Compatibility

Clown Rasboras are peaceful and friendly, which allows them to be kept in the same aquarium with many other species of comparable size. These fish prefer to stay in large shoals. It is recommended to keep a group of at least 8–10 individuals, as they may become timid if kept in smaller numbers.

Care and Maintenance

For a shoal of 8–10 Clown Rasboras, the optimal aquarium volume starts from 250 liters. When decorating, it is recommended to recreate conditions resembling their natural habitat. Sand substrate, driftwood, and shade-loving plants, which can be planted in dense groups, will be an excellent choice. Lighting should be subdued. Floating vegetation can also provide additional shade. The use of leaves from trees such as oak, birch, maple, or exotic Indian almond will be a useful decorative element. As they decompose, the leaves release tannins, which give the water its characteristic brown color. It is important to note that when keeping Clown Rasboras, water quality plays a key role, even more so than decor. It is necessary to maintain low hydrochemical parameters and avoid sharp fluctuations. Regular aquarium maintenance and the installation of a powerful filtration system will help maintain water at the proper quality level.

Diet

This species is omnivorous and readily accepts most common aquarium fish foods. The daily diet can consist of dry, frozen, or live foods of appropriate size.

Breeding and Reproduction

As is typical for most members of the carp family, Clown Rasboras are highly prolific and do not exhibit parental care for their offspring. Under favorable conditions, with sufficient hiding places, for example, in the form of dense vegetation, the fish will spawn regularly, and some fry are quite capable of surviving even in a community tank.

Diseases

Clown Rasbora is a hardy and undemanding fish. When suitable keeping conditions are met, health problems usually do not arise. Diseases can appear in cases of injury, contact with already sick fish, or a significant deterioration of habitat parameters (for example, in a dirty aquarium or with poor nutrition).

How to choose

When purchasing Clown Rasboras, choose active individuals that stay in a shoal and do not show signs of lethargy or a tendency to isolate themselves. Carefully inspect the fish for fin damage, ulcers, white spots, or unnatural growths on the body, as these symptoms may indicate infectious diseases. Avoid individuals with signs of emaciation or sunken bellies. Since this species is often confused with other members of the genus, ensure correct identification: Rasbora kalochroma has a characteristic coloration with two large dark spots on its sides and a reddish body hue. In the store, the fish should be kept in clean water, and their behavior should be natural for a schooling species. Remember that due to their timidity, they may appear paler in retail tanks than in a home environment with subdued lighting.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Clown Rasbora get?

An adult reaches 10 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Clown Rasbora need?

The recommended volume is 250 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Clown Rasbora need?

Temperature 23–28 °C, pH 5–7.5, hardness 1–10 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Clown Rasbora live?

Around 4 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Clown Rasbora aggressive?

Temperament: peaceful (regular). Keep this in mind when choosing tank mates.

How many Clown Rasbora should be kept together?

Recommended setup: group (8–10 individuals). Ignoring this is a common cause of stress and disease.

What does Clown Rasbora eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Clown Rasbora?

The scientific name of the species is Rasbora kalochroma, family Cyprinids (Cyprinidae). It also appears in the literature as: Leuciscus kalochroma, Rasbora kalachroma.

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Other scientific names and conservation status

Other scientific names
Leuciscus kalochroma, Rasbora kalachroma
Categories
Cyprinids
Conservation status
Least concernLC