About Chili Rasbora
The Chili Rasbora, also known as the Mosquito Rasbora, is one of the most stunning nano fish available in the aquarium hobby. Native to the acidic blackwater peat swamps of Borneo, Indonesia, these tiny fish pack an incredible visual punch with their intense red-orange bodies and contrasting black markings. Males display the most vibrant coloration, especially when competing for female attention or establishing dominance. At just over half an inch in length, they are true micro fish that require specialized care and appropriately sized tank mates. Their small size and demanding water parameters make them more suitable for intermediate aquarists, but their breathtaking beauty and interesting behaviors make the extra effort worthwhile. Chili rasboras are peaceful schooling fish that should be kept in groups, where they will display fascinating social hierarchies and spawning behavior. They are ideal inhabitants for specialized blackwater nano tanks or heavily planted aquascapes.
Care Guide
Care Requirements
Tank Setup
Chili rasboras require specialized blackwater or acidic conditions. Heavily planted nano tanks with leaf litter, driftwood, and botanicals replicate their natural habitat. Use indian almond leaves, alder cones, or peat to create tannins and lower pH. Dark substrate essential for color display. Very gentle filtration; they cannot tolerate strong currents. Floating plants help diffuse light.
Water Quality
- Temperature: 75-82°F (24-28°C)
- pH: 4.0-6.5 (acidic essential)
- Water Hardness: Soft (0-5 dGH)
- Ammonia/Nitrite: 0 ppm
- Nitrate: <10 ppm
Very specific water requirements. They require soft, acidic water to thrive and display best colors. Tannins from botanicals are highly beneficial. Stable parameters more important than perfect numbers.
Feeding
Extremely small mouths require specialized tiny foods:
- Powdered or crushed flake food
- Micro pellets designed for nano fish
- Baby brine shrimp
- Microworms
- Vinegar eels
- Infusoria for very small fry
Feed 2-3 tiny meals daily. They have small stomachs and need frequent small feedings.
Behavior & Compatibility
Peaceful but complex social dynamics. Keep in groups of 8-10 minimum, ideally 15-20+. Males display to each other and females, showing intense coloration during interactions. They establish pecking orders and may spar harmlessly. Occupy all water levels but prefer middle-bottom. Compatible only with other peaceful nano species. Easily outcompeted by larger fish.
Common Health Issues
- pH shock: Extreme sensitivity to pH changes; acclimate very slowly
- Starvation: Need appropriately tiny food; ensure they get enough
- Bacterial infections: Common in soft water; maintain pristine conditions
- Stress: Will lose color and hide; check parameters and school size
Breeding
Relatively easy to breed in proper conditions. Egg scatterers that prefer fine-leaved plants or moss. Soft, acidic, warm water triggers spawning. Males display intensely to females. No parental care. Eggs hatch in 24-48 hours. Fry are extremely tiny and require infusoria and microworms. Survival rates improve with heavy planting.
Tips for Success
- Use active peat filtration or botanicals to maintain acidic conditions
- Acclimate extremely slowly over 2+ hours using drip method
- Keep in larger schools for best behavior and color
- Feed multiple tiny meals daily with appropriately small food
- Monitor pH and hardness weekly; these are critical parameters
- House only with other peaceful nano species
- Dim lighting and tannins enhance their colors
- Perfect for blackwater biotope tanks