Nano Aquarium Fish Species Spotlight: Chili Rasboras (Boraras brigittae)

If you’ve been in the nano aquarium hobby for any length of time, you’ve probably heard whispers about these tiny red gems from Borneo. As someone who’s been breeding nano fish for over fifteen years, I can tell you that Chili Rasboras hold a special place in my fish room and my heart. These micro predators, barely reaching 2 centimeters in length, pack more personality and color into their tiny bodies than fish ten times their size. When I first imported my breeding stock from Indonesia back in 2009, I wasn’t prepared for how these little fireflies would transform a simple planted tank into a living work of art. Today, I’m sharing everything I’ve learned about keeping and breeding these spectacular nano fish, so you can experience the same joy they’ve brought to my aquariums.

Why Chili Rasboras Steal Every Aquarist’s Heart

The moment you see a school of Chili Rasboras darting through a heavily planted nano tank, you’ll understand why they’ve become the darling of the aquascaping world. Their deep crimson bodies, accented with a dark lateral stripe and translucent fins, create an almost surreal contrast against green aquatic plants. Unlike many nano fish that hide or blend into their surroundings, these bold little characters actively explore every corner of their environment. I’ve watched my breeding groups for countless hours, and they never cease to amaze me with their confident behavior and social interactions.

What really sets Chili Rasboras apart is their perfect suitability for nano aquariums. While many fish species are marketed as “nano” but really need larger spaces to thrive, Boraras brigittae actually prefers smaller, well-planted environments. A group of 8 to 12 individuals will thrive in a tank as small as 5 gallons, though I personally recommend 10 gallons or more for a proper breeding setup. Their peaceful temperament makes them ideal tankmates for other micro species like Pygmy Corydoras or small shrimp species. In all my years breeding these fish, I’ve never witnessed aggression beyond the occasional male displaying to competitors during spawning behavior.

Creating the Perfect Home for Your Chilis

Setting up the ideal environment for Chili Rasboras means recreating a slice of their native Borneo blackwater streams. These fish come from soft, acidic waters with plenty of leaf litter, submerged roots, and dense vegetation. In my breeding facility, I maintain the following water parameters:

Optimal Water Parameters:

• Temperature: 75-80°F (24-27°C)
• pH: 4.5-7.0 (ideally 5.5-6.5)
• Hardness: 1-5 dGH
• TDS: 50-150 ppm

The substrate choice matters less than the overall aquascape design. I’ve successfully kept Chilis on everything from bare bottom tanks to nutrient-rich planted substrates. What’s crucial is providing plenty of cover through plants and hardscape. Java moss, Java fern, Cryptocoryne species, and fine-leaved stem plants create the perfect backdrop. The key is establishing visual barriers and hiding spots while maintaining open swimming areas in the midwater column where these fish spend most of their time.

Filtration should be gentle, as Chili Rasboras come from slow-moving waters and can struggle in strong currents. I use sponge filters in most of my breeding tanks because they provide excellent biological filtration without creating excessive water movement. The sponges also cultivate microorganisms that fry can feed on after hatching. Lighting can be moderate to bright if you’re growing plants, but include floating vegetation or shaded areas where the fish can retreat when they feel stressed.

Feeding Your Chili Rasboras for Vibrant Color

Here’s where many aquarists go wrong with micro species: they assume any fish food will work. The truth is that Chili Rasboras have tiny mouths and specific nutritional needs that standard flake foods simply can’t meet. In the wild, these fish are micropredators, feeding on tiny insects, insect larvae, and zooplankton. Their diet is high in protein and rich in natural color-enhancing compounds called carotenoids.

I’ve experimented with virtually every food on the market over the years, and particle size is absolutely critical. Foods need to be small enough for their diminutive mouths, typically under 0.5mm for optimal feeding. This is where specialized products like Nano Fish Food Adult Meal become invaluable. This formula is specifically designed for micro species with appropriately sized particles and a protein-rich composition that mimics their natural diet. Since switching my breeding colony to this food three years ago, I’ve noticed improved coloration, better spawning frequency, and healthier fry development.

Daily Feeding Schedule:

1. Morning feeding: Small pinch of nano-specific dry food
2. Evening feeding: Live or frozen micro foods (baby brine shrimp, daphnia, or cyclops)
3. Fasting day: Once per week to prevent overfeeding

The secret to achieving that deep red coloration lies in variety and quality. While a high-quality nano food should form the staple diet, supplement 2-3 times weekly with live or frozen foods. I culture my own daphnia and grindal worms, but quality frozen options work excellently. Watch your fish during feeding; they should eagerly consume food within 2-3 minutes. Any food remaining after this time indicates overfeeding, which can quickly foul water in nano setups.

Breeding Chili Rasboras: Tips from the Pros

Breeding Chili Rasboras isn’t particularly difficult once you understand their requirements, but it does require attention to detail. Unlike egg-scattering species that spawn and forget, Boraras brigittae are continuous spawners in well-maintained aquariums. Females will scatter eggs among fine-leaved plants or spawning mops daily when conditions are optimal. The challenge isn’t getting them to spawn but raising the incredibly tiny fry.

I use two approaches in my facility: colony breeding in planted tanks and targeted pair breeding in smaller containers. For colony breeding, maintain a heavily planted 10-20 gallon tank with a ratio of two females per male. Dense moss (especially Java moss or Taxiphyllum) provides egg-laying sites and protects eggs from adult predation. While adults will eat their own eggs if given the chance, sufficient plant cover allows some fry to survive to maturity. I’ve had tanks where I never removed adults yet still found juvenile fish appearing among the plants every few weeks.

Breeding Setup Checklist:

• Separate breeding tank (2-5 gallons for pairs)
• Spawning mops or dense moss
• Aged water with parameters at ideal ranges
• Dim lighting or floating plants for security
• Gentle sponge filter with pre-filter sponge

For serious breeding efforts, I prefer the controlled approach. Condition males and females separately with high-quality foods for one week. Select the most colorful male and roundest female, then place them together in the evening in a small breeding container. They typically spawn within 24-48 hours, with the female scattering 5-15 tiny eggs among the spawning medium. Remove the adults immediately after spawning to prevent egg predation.

The fry are microscopic when they hatch after 24-36 hours and require infusoria or liquid fry food for the first week. I culture green water (suspended algae) specifically for this purpose, as it provides continuous feeding for these tiny babies. After 7-10 days, they’re large enough to accept freshly hatched baby brine shrimp. Growth is slow but steady, and by 8-12 weeks, they begin showing their characteristic red coloration.

Frequently Asked Questions

How many Chili Rasboras should I keep together?
These are schooling fish that feel most secure in groups of at least 8-10 individuals. In my experience, groups of 12-15 display the most natural behavior and vibrant coloration. Smaller groups tend to be skittish and hide more often.

Can Chili Rasboras live with shrimp?
Absolutely! They make excellent tankmates for Neocaridina and Caridina shrimp species. They won’t bother adult shrimp, though they may occasionally snack on newborn shrimplets. In well-planted tanks with plenty of cover, shrimp populations still thrive alongside these fish.

Why are my Chili Rasboras pale or washed out?
Pale coloration usually indicates stress, poor water quality, or inadequate nutrition. Check your water parameters first, ensure the tank has sufficient cover, and upgrade their diet to include high-quality nano-specific foods with color-enhancing ingredients. Stressed fish in bare tanks with bright lighting rarely show their best colors.

How long do Chili Rasboras live?
With proper care, these fish typically live 3-5 years in aquarium conditions. I’ve had exceptional individuals reach 6 years, though this is uncommon. Maintaining stable water parameters and providing excellent nutrition significantly impacts their lifespan.

What’s the difference between Chili Rasboras and other Boraras species?
The Boraras genus includes several similar nano species. Chili Rasboras (B. brigittae) are distinguished by their deep red coloration and dark lateral stripe. They’re often confused with B. merah (Phoenix Rasbora) which has more orange tones, or B. urophthalmoides (Exclamation Point Rasbora) which has a distinctive spot pattern rather than a stripe.

Do Chili Rasboras need a heater?
Unless you maintain your home at 75-80°F year-round, yes, a heater is essential. These tropical fish cannot tolerate temperature fluctuations or cool water. I use adjustable heaters in all my tanks to maintain stable temperatures, which is crucial for their immune system and overall health.

After years of working with hundreds of nano species, Chili Rasboras remain one of my top recommendations for anyone serious about the nano aquarium hobby. Their combination of stunning appearance, manageable care requirements, and fascinating behavior makes them perfect for both beginners and experienced aquarists. Whether you’re setting up your first planted nano tank or adding to an established community, these little red jewels will bring life, color, and movement to your aquascape. Remember that success with any nano species comes down to attention to detail: stable parameters, appropriate foods sized for tiny mouths, and an environment that mimics their natural habitat. Give these magnificent micro fish the care they deserve, and they’ll reward you with years of enjoyment and perhaps even the satisfaction of raising new generations in your own home. The nano aquarium world is full of amazing species, but few capture the magic quite like Boraras brigittae.