Species Snapshot
- Species Name: Boraras brigittae
- Common Names: chili rasbora, mosquito rasbora
- Size: 0.6 to 0.8 inches
- Lifespan: 4 to 6 years
- Native Distribution: Indonesia
Some of the smallest fish in the aquarium hobby, chili rasboras are ideal for nano tank setups. They grow up to less than an inch in length but what they lack in size they make up for in color. These fish are bright orange-red with dark stripes – some even have spots near the tail. If you’re looking for a colorful and entertaining addition to your nano tank, consider the chili rasbora.
Anatomy and Appearance
Also known as mosquito rasboras, chili rasboras are known for their bright red color. These fish are extremely small, growing between 0.6 and 0.8 inches in length at maturity. This is what earns them their classification as a nano fish.
These tiny fish have a streamlined torpedo-like shape. Their color ranges from red to deep orange with a solid or split black lateral line. Chili rasboras have only four fins: a single dorsal fin, caudal fin, pelvic fin, and anal fin. In most chili rasboras the fins are dotted with red and black color.
While related to other rasboras, a genus of fish in the family Cyprinidae, chili rasboras are unique in their anatomy. Whereas most rasboras have more vertebrae through the abdomen, chili rasboras and other Boraras species have more vertebrae near the caudal fin.
Ideal Aquarium Setup
Chili rasboras are sensitive to changes in water temperature and tank parameters. They’re generally considered an intermediate fish rather than a beginner fish and maintaining optimal tank conditions is essential if you hope to breed your chili rasboras. In the right conditions, these fish can live for 6 years or more. They will not thrive in a dirty tank.
Tank Size
Because they are so small, chili rasboras can be kept in a tank as small as 10 gallons for a group of ten fish. The larger the school, however, the more impressive it will look. For each gallon of water over 10 your tank can accommodate another 1 to 2 chili rasboras.
Keep in mind that you’ll need to include any other tank inhabitants when making your calculations. A 10-gallon tank is acceptable for a group of 10 shrimp, but you’ll need a larger tank if you want to keep shrimp with a school of chili rasboras.
Water Parameters
Chili rasboras are found in blackwater environments in their native habitat, so they can tolerate fairly acidic water. They are less tolerant, however, of changes in water quality and water temperature. It’s important to maintain a consistent water temperature with a programmable heater and to monitor the tank temperature with a thermometer. Not only should you prevent the water from getting too cold but avoid placing the tank in direct sunlight that might overheat the tank.
The ideal tank parameters for chili rasboras are:
- Temperature: 68°F to 82°F
- pH Level: 4.0 to 7.0
- Water Hardness: 3.0 to 12.0 dKH
High water quality is paramount for chili rasboras. They are very sensitive to ammonia and nitrates, so a weekly water change of 10% to 15% your tank volume is recommended. A quality filtration system is important as well, though it’s wise to limit the strength of flow to avoid stressing your fish.
Tank Décor
Nano fish prefer to be kept in larger schools in a fairly dense habitat, though they still need room to swim. Planted tanks are recommended and should be stocked with both rooted and floating plants. A lushly planted tank also protects chili rasboras from intense lighting. To mimic the native habitat of chili rasboras, include driftwood and tannin-rich leaf litter in the tank.
Diet and Feeding
While chili rasboras will accept a wide variety of foods, they are classified as micropredators. These fish thrive on a varied diet of live, frozen, and freeze-dried carnivorous foods like microworms, brine shrimp, tubifex worms, and chopped bloodworms. These fish may also accept flakes and pelleted foods.
To encourage their brightest coloration, feed chili rasboras a varied diet. Because they are so small, however, it’s important to avoid overfeeding. Feed in very small amounts – only as much as your fish can consume in a minute or two. Uneaten fish food will breakdown and affect the water quality in your tank, potentially making your fish sick.
All foods for chili rasboras need to be very small. Flakes and pellets should be crushed while live and frozen foods should be finely chopped.
Temperament and Tank Mates
While chili rasboras prefer to be kept in schools with their own species, they can get along with other small, peaceful fish in a community nano tank environment. They are not a good fit for larger or more aggressive fish that might consider them prey.
Chili rasboras are generally very peaceful – they do not tend to chase or nip at the fins of other fish. They do best in large schools with their own species. The larger the school, the more stunning the effect in your tank in terms of color and activity.
While chili rasboras generally aren’t the best choice for community tanks, they do well in shrimp tanks because of their timid nature. They aren’t big enough to feed on most shrimp and they tend to stick to the middle or upper water column.
Breeding Green Chili Rasbora
Though it’s a little tricky, you can distinguish between male and female chili rasboras by their color and shape. Males have brighter coloration than females and their color intensifies when they’re looking for mates. Male chili rasboras also tend to be thinner and more streamlined than females – more bullet-shaped than rounded.
During courtship, male chili rasboras develop brighter, more intense coloration and female chili rasboras develop rounder bellies in preparation for egg carriage. Male chili rasboras can become territorial during breeding, so it’s important to provide your fish with ample tank space.
Female chili rasboras are egg scatterers and neither sex cares for the eggs at all after they’ve been laid. Chili rasboras are known for cannibalizing their own eggs, so it’s wise to remove the adults from the tank if you hope to rear the fry. Densely planted tanks may provide enough cover for eggs and fry.
Other Interesting Facts
- Chili rasboras are native to Indonesia, specifically to southwestern Borneo. They’re naturally found in blackwater streams and pools, even pea swamps where the pH is as low as 4.0.
- While chili rasboras are by no means expensive, they can be difficult to find in pet stores. They can, however, be found easily online.
- Chili rasboras are popular for their active behavior and bright coloration, but their color may change depending on tank conditions. These fish will exhibit their brightest coloration when water parameters are optimal and stress in the tank is low.
- These rasboras display unpredictable schooling behavior and while they’re typically found in the top or middle of the water column, they can sometimes be found eating and swimming at the lower levels of the tank.
- Chili rasboras breed readily in optimal conditions but you can improve the odds of breeding by keeping them at a ratio of 1 to 2 females per male.
Visit Shrimpy Business and get your chili rasbora!