Harlequin Rasbora fish Care Guide: Feeding,Breeding Tips

The Harlequin Rasbora is a colorful, peaceful freshwater fish perfect for community tanks

Known for its striking colors and ease of care, it adds lively beauty to any aquarium setup.

Harlequin Rasbora (Trigonostigma heteromorpha) Profile

Minimum Tank Size10 gallons
Life Span5-8 years
SizeUp to 2 inches (5 cm)
CompatibilityExcellent community fish
TemperamentSchooling and peaceful
group of Harlequin Rasbora

Tank Setup for Harlequin Rasbora

Tank Size

  • Minimum: 20 gallons
  • Ideal: 30 gallons or more for larger schools

Water Parameters

  • Temperature: 72-81°F (22-27°C)
  • pH: 6.0-7.8
  • Hardness: 2-15 dGH


  • Use a high-quality filter suitable for the tank size. A canister filter or hang-on-back filter is recommended for efficient filtration.
  • Ensure moderate water flow to mimic their natural habitat.


  • Fine gravel or sand
  • Darker substrates preferred to enhance their colors


  • Moderate lighting to support plant growth and natural behavior
  • Avoid overly bright lights

Plants and Decorations

  • Heavily planted tank with live plants such as Java Fern, Anubias, and Cryptocoryne
  • Floating plants like Duckweed or Frogbit to diffuse light
  • Use driftwood and rocks to create hiding spots and mimic natural habitat

Tank Mates

  • Peaceful community fish such as Tetras, Corydoras, and other small, non-aggressive species
  • Avoid larger or aggressive fish that may bully or eat them


  • Omnivorous diet: high-quality flake food, micro pellets, and frozen or live foods like daphnia, brine shrimp, and bloodworms
  • Feed small amounts 2-3 times a day


  • Perform regular water changes (25-30% weekly) to maintain water quality
  • Monitor water parameters regularly

Behavior and Social Structure

  • Harlequin Rasboras are schooling fish; keep them in groups of at least 8-10
  • They thrive in a well-maintained, stable environment.

Feeding Harlequin Rasbora

Harlequin Rasbora aquariums

Feeding Harlequin Rasbora can be straightforward, but it’s essential to ensure they receive a balanced diet to maintain their health and vibrant colors. Here’s a comprehensive guide on how to feed your Harlequin Rasbora:

Diet Overview

Harlequin Rasboras are omnivores, meaning they eat both plant and animal matter. In their natural habitat, they consume small insects, larvae, and plant debris. In an aquarium, a varied diet is key to their well-being.

Types of Food

Flake Food:

  • High-quality flake food should be a staple in their diet. Choose flakes that are specifically formulated for tropical fish.


  • Micro pellets are also suitable for Harlequin Rasboras. Ensure the pellets are small enough for their mouths.

Frozen and Live Foods:

  • Brine Shrimp: A great source of protein. Can be given once or twice a week.
  • Daphnia: Another protein-rich option that helps with digestion.
  • Bloodworms: High in protein, but should be fed sparingly to avoid digestive issues.
  • Microworms and Vinegar Eels: Excellent for conditioning fish for breeding.

Vegetable Matter:

  • Although not a significant part of their diet, including some blanched vegetables like spinach or peas can be beneficial.

Feeding Schedule

  • Frequency: Feed Harlequin Rasboras small amounts two to three times a day.
  • Quantity: Only provide what they can consume within 2-3 minutes. Overfeeding can lead to water quality issues and health problems.

Tips for Feeding

Variety: Rotate different types of food to ensure they get a balanced diet.

Observation: Watch them during feeding to ensure all fish are eating. Harlequin Rasboras are peaceful and may be outcompeted by more aggressive eaters.

Supplementation: Occasionally add a vitamin supplement to their food to boost their immune system and coloration.

Special Considerations

Breeding: If you are conditioning Harlequin Rasboras for breeding, increase the frequency of high-protein foods like brine shrimp and bloodworms.

Young Fish: Fry and juvenile Harlequin Rasboras require smaller, more frequent feedings. Crushed flake food and baby brine shrimp are ideal for them.

Common Mistakes

  • Overfeeding: This can lead to obesity and poor water quality. Stick to small, frequent feedings.
  • Monotonous Diet: Relying solely on flake food can result in nutritional deficiencies. Mix up their diet regularly.

Breeding Harlequin Rasbora

Breeding Harlequin Rasbora can be a rewarding experience, as these fish are relatively easy to breed in the right conditions. Here’s a detailed guide to help you successfully breed Harlequin Rasboras:

Preparing for Breeding

  1. Selecting Breeding Pairs
  • Healthy Adults: Choose healthy, vibrant adults. Mature females are usually fuller-bodied, especially when filled with eggs, while males are slimmer and more colorful.
  • Ratio: A good breeding ratio is one male to two females.

Breeding Tank Setup

  • Tank Size: A 10-20 gallon tank is sufficient for breeding.
  • Water Conditions:
    • Temperature: Maintain the water temperature between 76-80°F (24-27°C).
    • pH: A slightly acidic pH of 6.0-6.5 is ideal.
    • Hardness: Soft water (2-5 dGH) is preferred.
  • Substrate: Use a dark substrate to mimic their natural environment.
  • Plants: Include fine-leaved plants like Java moss or spawning mops, which provide a place for the fish to lay their eggs.
  • Filtration: Use a gentle sponge filter to avoid sucking up the eggs or fry.

Conditioning the Breeders

  • Diet: Feed the breeding pair a high-protein diet, including live or frozen foods such as brine shrimp, daphnia, and bloodworms, for about one to two weeks before breeding.

Breeding Process

Introducing the Pair

  • Introduce the conditioned male and female(s) to the breeding tank in the evening. The spawning usually occurs in the early morning.

Spawning Behavior

  • Courtship: Males will display vibrant colors and perform a courtship dance to attract females.
  • Egg Laying: Females will lay adhesive eggs on the undersides of leaves or on the spawning mop. Each female can lay up to 100 eggs.
  • Fertilization: Males will follow the females, fertilizing the eggs as they are laid.

Post-Spawning Care

  • Remove Adults: Once spawning is complete, remove the adults to prevent them from eating the eggs.
  • Egg Care: The eggs will hatch in about 24-36 hours. The tiny fry will initially be attached to surfaces.

Raising the Fry

Initial Feeding

  • Infusoria: For the first few days, feed the fry infusoria or other microscopic foods.
  • Baby Brine Shrimp: After a few days, you can start feeding them newly hatched brine shrimp or finely crushed flake food.

Tank Maintenance

  • Water Quality: Maintain excellent water quality with frequent, small water changes. Avoid large changes that can shock the fry.
  • Growth: As the fry grow, you can gradually increase the size of their food.

Monitoring Growth

  • Growth Stages: Monitor the fry as they develop. Within a few weeks, they should start to resemble miniature versions of the adult Harlequin Rasboras.
  • Tank Size: As they grow, consider moving them to a larger tank to provide ample space.

Common Issues and Troubleshooting

Egg Fungus

  • If you notice eggs developing fungus, consider using an anti-fungal treatment safe for fish eggs.

Poor Hatching Rates

  • Ensure optimal water conditions and provide a nutritious diet to the breeding pair.

Fry Mortality

  • Maintain stable water conditions and provide proper nutrition to reduce fry mortality.

Harlequin Rasbora Tank Mates

  • Lambchop Rasbora
  • Chili Rasbora
  • Neon Tetra
  • Cardinal Tetra
  • Rummynose Tetra
  • Pygmy Corydoras
  • Panda Corydoras
  • Honey Gourami
  • Sparkling Gourami
  • Zebra Danio
  • Ember Tetra
  • Cherry Shrimp
  • Amano Shrimp
  • Nerite Snails


Can rasboras live with tetras?

Yes, rasboras can live with tetras as both are peaceful and compatible in community tanks.

What is the smallest rasbora?

The Chili Rasbora (Boraras brigittae) is the smallest rasbora, growing up to 0.8 inches (2 cm).

Do rasboras produce a lot of waste?

No, rasboras do not produce a lot of waste compared to larger fish species.

How many harlequin rasboras should I keep?

Keep at least six Harlequin Rasboras together to ensure they feel secure and exhibit natural schooling behavior.

Can guppies go with rasboras?

Yes, guppies can live with rasboras as both are peaceful and get along well in a community tank.

Do rasboras eat baby shrimp?

Yes, rasboras may eat baby shrimp if they fit in their mouths.

Can neon tetras live with rasboras?

Yes, neon tetras can live with rasboras as both are peaceful and have similar water requirements.

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