Chili Rasbora Care Guide
3 min read · Updated Jun 2026
Chili rasboras (Boraras brigittae) are tiny, glowing red nano fish that school in soft, planted blackwater tanks. At under an inch long, a shoal of them turns a small planted tank into a living ember field.
In this guide
Species Snapshot
- Tank size
- 5+ gallons
- Temperature
- 75-82°F
- pH
- 4.0-7.0
- GH
- 1-6 dGH
- Difficulty
- Intermediate
- Lifespan
- 4-8 years
- Adult size
- 0.7 in
- Diet
- Micropredator
Chili rasboras prove that you do not need a big tank to keep a stunning fish. A shoal of these inch-long, ember-red nano fish in a soft, planted blackwater tank is one of the most beautiful setups in the hobby — but their small size and water preferences make them an intermediate fish, not a starter.
What you need
Chili rasboras want a heavily planted nano tank, soft acidic water, and a shoal large enough to feel safe. The planting and the group size are what bring out their color and confidence.
Aqueon 10 Gallon Glass Aquarium
The 10-gallon is the most forgiving starter size — cheap, stable, and easy to find.
A 10 gallon is a sweet spot — big enough for a proper shoal of 10-15, small enough to keep densely planted and intimate.
Tank size and setup
Aim for a wide, well-planted footprint with floating plants to dim the light and driftwood or leaf litter to release tannins. Chili rasboras are weak swimmers, so keep flow gentle.
Hygger Aquarium Double Sponge Filter (Small)
Shrimp-safe filtration with no intake tube to suck in babies; gentle flow bettas love.
A sponge filter gives the gentle current they prefer and won't suck in these tiny fish. Adding Indian almond leaves recreates their natural blackwater habitat and brings out richer color.
Indian Almond (Catappa) Leaves
Release tannins and grow biofilm shrimp graze on; mild antibacterial benefits.
Water parameters
Chili rasboras come from soft, acidic peat swamps:
- Temperature: 75-82°F
- pH: 4.0-7.0 (acidic preferred)
- GH: 1-6 dGH (soft)
They will adapt to neutral water, but soft and slightly acidic is where they color up and breed. A small heater keeps the tropical temperature stable.
Eheim Jager 50W Heater
Accurate German-made heater with a reliable thermostat for small tanks.
Diet and feeding
Here is the catch with such a tiny fish: most standard food is too big for their mouths. They are micropredators that need small foods:
- Crushed or powdered flake
- Micro pellets and nano-sized granules
- Frozen baby brine shrimp and cyclops
- Live microfauna in a mature, planted tank
Feed small amounts a couple of times a day and watch that everyone is actually getting fed.
Common mistakes
- Keeping too few — a small group hides and stays pale and stressed
- Feeding food that is too large for their tiny mouths
- Strong filter flow that exhausts these weak swimmers
- Adding them to a brand-new tank before microfauna and biofilm establish
Tank mates
Chili rasboras are peaceful and ideal for nano communities. The best companions are dwarf shrimp, snails, and other calm nano fish like pygmy corydoras. Avoid anything large or boisterous — bigger fish will either eat them or intimidate them into permanent hiding.
Plan a nano blackwater tank
Use our Tank Builder to spec a planted nano setup — tank, gentle filter, heater, light, and substrate — perfect for chili rasboras and shrimp.
Build my tank kit →Breeding
In a mature, soft-water planted tank, chili rasboras often breed on their own. They are continuous scatter-spawners that lay eggs among moss and fine-leaved plants. They will eat their own eggs and fry, so a dense moss carpet (or a separate grow-out) is how shrimplet-sized fry survive.
Recommended products
Java Moss (Portion)
Shrimp graze the biofilm it grows and babies hide in it — a shrimp-tank staple.
Seachem Prime Water Conditioner
The gold standard dechlorinator — also detoxifies ammonia and nitrite during cycling.
Give chili rasboras a planted, soft-water nano tank and a shoal big enough to feel safe, and a dozen ember-red fish will light up a tank no bigger than a desktop.