Harlequin Rasbora Care Guide
Harlequin rasboras are striking schooling fish with distinctive orange-pink bodies and black triangular patches. Hardy, peaceful, and active swimmers, they make an excellent choice for planted community tanks.
Quick Facts
Tank Size Requirements
Pro Tip: Longer tanks are better than tall tanks
Harlequin rasboras are active horizontal swimmers. A 20-gallon long provides more swimming space than a 20-gallon tall, allowing them to display their beautiful schooling behavior.
Minimum Requirements
- Minimum: 10 gallons for a school of 6 (20+ gallons preferred)
- Plants: Heavily planted tanks mimic their natural blackwater habitat
- Lighting: Subdued lighting with floating plants brings out best colors
- Filter: Gentle to moderate flow, they prefer calm waters
- Lid: Required, rasboras are skilled jumpers when startled
These fish thrive in densely planted aquascapes with plenty of open swimming space in the middle. Dark substrates and tannin-stained water from driftwood or Indian almond leaves enhance their coloration dramatically.
Ideal Water Parameters
Blackwater Setup (Optional)
In the wild, harlequin rasboras inhabit peat swamp forests with tea-colored water. Adding Indian almond leaves, driftwood, or alder cones creates tannin-rich water that reduces stress, enhances coloration, and provides mild antibacterial properties. This is optional but highly recommended for breeding.
Diet & Feeding
Harlequin rasboras are omnivores that eagerly accept most foods. A varied diet brings out their best colors and keeps them healthy and active. They feed primarily in the middle and upper water column.
Recommended Foods
- Staple: High-quality micro pellets or tropical flakes
- Protein: Frozen or live daphnia, brine shrimp, bloodworms (2-3x per week)
- Color enhancers: Foods containing astaxanthin or spirulina
- Variety: Rotate between 3-4 different foods for complete nutrition
Feeding Schedule
- Frequency: 2-3 small meals per day rather than one large feeding
- Amount: Only what they can consume in 2-3 minutes
- Fasting: One fast day per week aids digestion
Tank Mate Compatibility
Harlequin rasboras are peaceful mid-water swimmers that pair well with bottom dwellers and other non-aggressive community fish. Their small size makes them targets for larger fish.
Common Diseases & Treatment
Ich (White Spot Disease)
White salt-like spots on body and fins, scratching against objects, clamped fins
Parasitic infection triggered by stress, temperature swings, or new fish
Raise temp to 82-86°F, add aquarium salt, ich medication if needed
Fin Rot
Frayed, disintegrating fins with white or red edges. Bacterial infection from poor water quality.
Rx: Water changes + antibacterials
Columnaris
White cotton-like patches on body or mouth, rapid breathing. Highly contagious bacterial infection.
Rx: Quarantine + antibiotics immediately
Prevention is the best medicine
Harlequin rasboras are hardy fish when kept in proper conditions. Maintain stable temperature, pristine water quality, and quarantine new arrivals to prevent most diseases.
Quick Tips
- Keep at least 6 rasboras together, larger schools of 10+ show the best behavior
- Use a tight-fitting lid, these fish jump when startled or during spawning
- Add tannins with Indian almond leaves or driftwood for enhanced coloration
- Provide plenty of plants but leave open swimming space in the middle
- Subdued lighting brings out their orange and pink colors beautifully
- Acclimate slowly, rasboras are sensitive to sudden parameter changes
- They breed on the underside of broad leaves like Cryptocoryne or Anubias
Frequently Asked Questions
How many harlequin rasboras should I keep?
A minimum of 6, but 10 or more is ideal. Larger schools display more natural behavior, better coloration, and reduced stress. They will swim together in a tight formation.
Can harlequin rasboras live with bettas?
Yes, they can make good tank mates in a 20+ gallon tank with plenty of plants. Rasboras are fast swimmers that stay in the middle water column, away from territorial bettas. However, monitor for aggression from individual bettas.
Why are my rasboras losing color?
Pale coloration usually indicates stress from poor water quality, incorrect temperature, lack of hiding spots, or insufficient school size. Dark substrates, tannins, and proper nutrition also bring out their colors.
How can I tell male from female harlequin rasboras?
Females are larger and rounder, especially when full of eggs. Males are slimmer with a more angular black patch that extends further down the body. Males also display brighter colors when courting.
Related Resources
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