Chili rasbora care: water, tank size and the mistake most keepers make
Chili rasboras are the best-looking nano fish in the hobby and one of the least tolerant of the wrong water. Get the water right and they are easy.
In the wild, Boraras brigittae lives in tannin-stained, very soft, acidic water with almost no dissolved minerals. That environment is not a preference — it is the reason the fish has no tolerance for osmotic stress. In hard water they survive, but the red fades, feeding slows, and lifespan shortens.
What they need
- Soft water (below 8 dGH). If your tap water is hard, mix it with RO or use botanical tannins.
- A stable pH between 5.0 and 7.0 — stable matters more than a specific number.
- A mature tank with biofilm on wood and plants; they graze constantly.
- Dense floating or stem plants. Chilis are shy in open water and show colour when they feel covered.
- A group of at least eight. A lone chili hides and stops eating.
Feeding
Their mouths are tiny. Micro pellets work if they are genuinely micro, but the reliable foods are live or frozen daphnia, baby brine shrimp and cyclops. Feed small amounts twice a day rather than one larger feed — uneaten food in a 20-litre tank is an ammonia event.
Adding chilis to a freshly cycled hard-water tank at week four. Wait until the tank has been stable for a month, and test GH and KH — not just pH — before you buy.
What to log
For a blackwater nano tank, log pH, GH (or KH), temperature and nitrate. A pH that drifts upward between water changes means your buffering is being consumed or your top-off water is too hard — both are visible in a log and invisible in a single test.
Frequently asked
Can chili rasboras live in a 5-gallon tank?
Why are my chili rasboras losing colour?
Honey gourami
A peaceful labyrinth fish that suits a planted 10-gallon. Slow water, floating cover, and one per tank — the rest is easy.
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A 2.5 cm schooling cory that actually works in a 10-gallon — if the substrate is sand and the group is big enough.
Read →Otocinclus
The best algae eater for a small planted tank — and the fish most often lost in the first month, because a new tank has no biofilm to eat.
Read →Stop guessing what your tank did last week
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