Chili Rasboras: A Comprehensive Guide

Chili Rasboras (Boraras brigittae), also known as Mosquito Rasboras, are tiny freshwater fish renowned for their vibrant colors and peaceful nature. This guide covers everything you need to know about Chili Rasboras, from their natural distribution and habitat to their dietary needs and spawning practices.

Distribution and Habitat

Chili Rasboras are native to the blackwater streams and peat swamps of South Kalimantan and Central Kalimantan in Borneo, Indonesia. These fish thrive in slow-moving, shallow waters that are heavily shaded by dense vegetation, resulting in soft, acidic water with a dark, tannin-stained appearance.

Size and Appearance

Chili Rasboras are one of the smallest aquarium fish, growing to a maximum size of about 0.8 inches (2 cm). They are easily recognizable by their bright red coloration and the black horizontal stripe running along their body, with males being more intensely colored than females.

Water Parameters

Maintaining optimal water conditions is crucial for the health of Chili Rasboras:

  • Temperature: 68-82°F (20-28°C)
  • pH: 4.0-7.0
  • Hardness: 0-5 dGH

These fish thrive in well-maintained aquariums with soft, acidic water, low lighting, and gentle filtration to mimic their natural blackwater habitat.

Tank Mates

Chili Rasboras are peaceful and social fish, making them ideal for nano tanks and community setups with other small, non-aggressive species. Suitable tank mates include:

  • Other Boraras species
  • Small tetras
  • Pygmy Corydoras
  • Dwarf shrimp
  • Snails

Avoid housing them with larger or more boisterous fish that might intimidate or outcompete them for food.


In the wild, Chili Rasboras are micropredators, feeding on small invertebrates and zooplankton. In captivity, they thrive on a varied diet:

  • High-quality micro-pellets or nano fish food
  • Live or frozen foods such as daphnia, baby brine shrimp, and microworms
  • Occasionally supplemented with finely crushed flake food

A varied diet ensures their vibrant coloration and overall health.


Chili Rasboras are active and social, typically found in groups. They exhibit fascinating schooling behavior, often swimming together in tight formations. They are best kept in groups of at least six to promote natural behaviors and reduce stress.


Breeding Chili Rasboras in captivity is relatively straightforward, making them a favorite among nano tank enthusiasts. Key points include:

  1. Conditioning: Feed the breeding group a high-protein diet, including live and frozen foods, for several weeks.
  2. Breeding Tank: Set up a separate breeding tank with soft, slightly acidic water and a temperature around 78°F (26°C). Provide plenty of fine-leaved plants or spawning mops for egg-laying.
  3. Spawning Process: Males display intense coloration and court females, who scatter adhesive eggs among the plants. Remove the adults after spawning to prevent egg predation.
  4. Hatching: Eggs typically hatch within 24-36 hours. Feed the fry infusoria or liquid fry food until they are large enough to consume baby brine shrimp.

Fun Facts

  • Chili Rasboras are among the smallest fish in the aquarium hobby, making them perfect for nano tanks.
  • Their bright red coloration intensifies in well-maintained, low-stress environments.
  • These fish are excellent indicators of water quality; they thrive in clean, well-oxygenated water and quickly show signs of stress in suboptimal conditions.


Chili Rasboras, with their vibrant colors and peaceful demeanor, make a delightful addition to any freshwater aquarium. By understanding their natural habitat, dietary needs, and care requirements, aquarists can ensure these charming fish thrive in captivity. Whether you're a novice or an experienced fish keeper, Chili Rasboras offer a glimpse into the world of dynamic and interactive nano fish.

For more insights on freshwater fish care, visit Steenfott Aquatics and explore our extensive collection of resources and community forums. Happy fishkeeping!

Looking to add Chili Rasboras to your aquarium? We recommend purchasing from trusted suppliers like The Wet Spot Tropical Fish and Dan's Fish for high-quality, healthy fish. These reputable retailers offer a great selection and expert advice to ensure you find the perfect fish for your tank.