Photo: VivienneHarper (CC BY-SA 3.0) — via Wikimedia Commons
Chili Rasbora (Boraras brigittae)
Barely 2 cm of blazing red — this shoaling nano fish turns a planted blackwater tank into a living jewel box.
Will it live with a Chili Rasbora?
We compare each fish against your chili rasbora on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Assassin Snail✅ CompatiblePeaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Celestial Pearl Danio✅ CompatiblePeaceful · 2 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Celestial Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
- Cherry Shrimp✅ CompatiblePeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Crystal Red Shrimp✅ CompatiblePeaceful · 2.5 cm · Hard care · 20–24 °C (68–75 °F)
- Both are peaceful, and their water overlaps around 22–24 °C — no size, zone or temperament conflicts.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Crystal Red Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Dawn Tetra✅ CompatiblePeaceful · 2.5 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Dawn Tetra in a shoal of 8+ or it gets stressed and nippy.
- Dwarf Spotted Rasbora✅ CompatiblePeaceful · 2.5 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Ember Tetra✅ CompatiblePeaceful · 2 cm · Easy care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Ember Tetra in a shoal of 8+ or it gets stressed and nippy.
- Emerald Dwarf Danio✅ CompatiblePeaceful · 2 cm · Medium care · 20–24 °C (68–75 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Exclamation Point Rasbora✅ CompatiblePeaceful · 2 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Exclamation Point Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Glowlight Danio✅ CompatiblePeaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Gold Ring Danio✅ CompatiblePeaceful · 3 cm · Easy care · 18–26 °C (64–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Gold Ring Danio in a shoal of 8+ or it gets stressed and nippy.
- Green Neon Tetra✅ CompatiblePeaceful · 2.5 cm · Hard care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Green Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
- Hummingbird Tetra✅ CompatiblePeaceful · 1.8 cm · Hard care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Hummingbird Tetra in a shoal of 8+ or it gets stressed and nippy.
- Lambchop Rasbora✅ CompatiblePeaceful · 3 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Lambchop Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Malaysian Trumpet Snail✅ CompatiblePeaceful · 3 cm · Easy care · 21–27 °C (70–81 °F)
- Compatible on the things that matter: shared water near 22–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Neon Blue Rasbora✅ CompatiblePeaceful · 2.5 cm · Medium care · 23–26 °C (73–79 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Neon Blue Rasbora in a shoal of 10+ or it gets stressed and nippy.
- Neon Green Rasbora✅ CompatiblePeaceful · 2 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Neon Green Rasbora in a shoal of 10+ or it gets stressed and nippy.
- Neon Tetra✅ CompatiblePeaceful · 3 cm · Easy care · 20–26 °C (68–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Neon Tetra in a shoal of 6+ or it gets stressed and nippy.
- Nerite Snail✅ CompatiblePeaceful · 2.5 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Ramshorn Snail✅ CompatiblePeaceful · 2 cm · Easy care · 20–28 °C (68–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Red Lip Nerite Snail✅ CompatiblePeaceful · 2 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Ruby Tetra✅ CompatiblePeaceful · 2 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
- Strawberry Rasbora✅ CompatiblePeaceful · 2 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Strawberry Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Tucano Tetra✅ CompatiblePeaceful · 1.7 cm · Hard care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Tucano Tetra in a shoal of 10+ or it gets stressed and nippy.
- Black Darter Tetra⚠️ With cautionSemi-aggressive · 4 cm · Hard care · 21–28 °C (70–82 °F)
- Black Darter Tetra is semi-aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Watch for Black Darter Tetra picking off any chili rasbora small enough to fit in its mouth.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Expect Black Ruby Barb to harass Chili Rasbora at times; give dense cover and watch them at feeding.
- Black Ruby Barb may hunt Chili Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Black Skirt Tetra to harass Chili Rasbora at times; give dense cover and watch them at feeding.
- Watch for Black Skirt Tetra picking off any chili rasbora small enough to fit in its mouth.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blue Turbo Snail⚠️ With cautionPeaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
- pH preferences only just meet (Chili Rasbora 5.5–7 vs Blue Turbo Snail 7.5–8.5) — target the overlap and acclimate slowly.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Desert Goby is semi-aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Desert Goby may hunt Chili Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Endler's Livebearer⚠️ With cautionPeaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
- One likes softer water and the other harder (1–8 vs 10–25 dGH) — a compromise, not a perfect match.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Endler's Livebearer in a shoal of 6+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra clearly outsizes Chili Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Watch for GloFish Tetra picking off any chili rasbora small enough to fit in its mouth.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Odessa Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Odessa Barb to harass Chili Rasbora at times; give dense cover and watch them at feeding.
- Chili Rasbora is small enough to tempt Odessa Barb; only risk it in a densely planted setup with hiding spots.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
- Pea Puffer⚠️ With cautionSemi-aggressive · 2.5 cm · Medium care · 24–28 °C (75–82 °F)
- Pea Puffer is semi-aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Rainbow Emperor Tetra⚠️ With cautionSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Rainbow Emperor Tetra clearly outsizes Chili Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Watch for Rainbow Emperor Tetra picking off any chili rasbora small enough to fit in its mouth.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
- Scarlet Badis⚠️ With cautionSemi-aggressive · 2 cm · Medium care · 22–27 °C (72–81 °F)
- Scarlet Badis is semi-aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Expect Serpae Tetra to harass Chili Rasbora at times; give dense cover and watch them at feeding.
- Chili Rasbora is small enough to tempt Serpae Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Serpae Tetra in a shoal of 6+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Silvertip Tetra clearly outsizes Chili Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Chili Rasbora is small enough to tempt Silvertip Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Tiger Badis is semi-aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Tiger Badis may hunt Chili Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Alligator Gar (250 cm) is big enough to swallow the 2 cm Chili Rasbora whole.
- Alligator Gar is aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Chili Rasbora is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
- Clown Knifefish is aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Chili Rasbora is bite-sized to a 100 cm predatory fire eel — it will be eaten.
- Expect Fire Eel to harass Chili Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Chili Rasbora is bite-sized to a 90 cm koi — it will be eaten.
- One likes softer water and the other harder (1–8 vs 9–18 dGH) — a compromise, not a perfect match.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Size gap is too large (120 vs 2 cm): Redtail Catfish will treat Chili Rasbora as food.
- Redtail Catfish is aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Spotted Gar (90 cm) is big enough to swallow the 2 cm Chili Rasbora whole.
- Spotted Gar clearly outsizes Chili Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Wels Catfish (300 cm) is big enough to swallow the 2 cm Chili Rasbora whole.
- Wels Catfish is aggressive and may chase or nip the smaller Chili Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Wolf Cichlid (72 cm) is big enough to swallow the 2 cm Chili Rasbora whole.
- Wolf Cichlid clearly outsizes Chili Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Chili Rasbora care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 2 cm (0.8 in)
- Min tank size
- 20 L (5.3 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 5.5–7
- Hardness
- 1–8 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Cyprinidae
- Origin
- Southwest Borneo — blackwater peat-swamp streams of South Kalimantan, Indonesia
What is a Chili Rasbora?
The chili rasbora (Boraras brigittae) is one of the smallest fish kept in the hobby, reaching a maximum of just 2 cm (under an inch) as an adult. What it lacks in size it more than compensates for in colour: males are an intense, almost luminous red, broken by a bold black lateral stripe and black fin margins. A mature shoal of twelve or more moving through a dark, heavily planted aquarium is among the most visually arresting sights a nano tank can offer.
Despite their jewel-box appearance, chili rasboras are not a fish for beginners. They are fragile in poor water, reluctant to colour up in the wrong conditions, and easily intimidated by anything large or boisterous in the tank. Get the habitat right, though, and they reward that effort every day. They belong to the genus Boraras, a group of miniature cyprinids from Southeast Asia, and are sometimes sold under the name mosquito rasbora or brigittae rasbora.
Where do Chili Rasboras come from?
Chili rasboras are native to the blackwater peat-swamp streams of South Kalimantan in southwest Borneo, Indonesia. Their wild habitat is as specific as it is striking: shallow, slow-moving water flowing through dense tropical forest, stained dark amber by tannins from decaying leaf litter and peat. The water in these systems is exceptionally soft, with very low dissolved mineral content, and often acidic to the point of pH 4–5. Light filters through the forest canopy in dappled patches, and the substrate is a deep layer of decomposing leaves.
Understanding this origin is the key to good chili rasbora care. The fish are adapted to warm, dark, chemically stable, mineral-poor water — and they will tell you quickly, by going pale and hiding, when conditions fall short of that.
What size tank does a Chili Rasbora need?
The minimum recommended tank size is 20 litres (about 5 gallons), but a 30–40 L (8–10 gal) aquarium gives far more margin for stable water quality and allows a larger, more confident shoal. Chili rasboras are mid-water swimmers and do not need a tall tank — a shallow, wide footprint gives them more open swimming area and makes planting easier.
Because they are so small, chili rasboras are vulnerable to strong filtration current. Use a sponge filter or fit a baffle to a hang-on-back filter to keep the flow gentle. The tank must be fully cycled before you add them — they are acutely sensitive to ammonia and nitrite. A lid or close-fitting cover is also important: they are capable jumpers despite their size. Plant densely with fine-leaved species (java moss, hornwort, microsword), add some floating cover to diffuse light, and consider a dark substrate to make their red colouration pop.
What water parameters do Chili Rasboras need?
- Temperature: 22–28 °C (72–82 °F). Aim for the middle of that range, around 24–26 °C (75–79 °F), for everyday keeping.
- pH: 5.5–7.0. Captive-bred stock tolerates the upper end, but colours and activity are noticeably better in softer, more acidic water.
- Hardness: 1–8 dGH — very soft to moderately soft. Hard tap water is a long-term problem; if yours exceeds 8 dGH, consider blending with RO or using a blackwater conditioner.
Tannins from Indian almond leaves, dried alder cones or a small bag of peat in the filter will shift pH downward, soften the water slightly, and release humic acids that mimic the species’ wild habitat. The water will turn amber — that is normal and beneficial, not a water-quality problem. Stability is paramount: sudden pH or temperature swings stress these fish far more than a reading that is slightly off the ideal target.
What do Chili Rasboras eat?
Chili rasboras are omnivores, but their tiny mouths place hard limits on food size. Standard flake is usually too large and must be crumbled finely; purpose-made micro pellets (0.5–1 mm) are a better staple. Rotate with small live and frozen foods for best health and colouration: baby brine shrimp (newly hatched nauplii are ideal), micro worms, Cyclops, and daphnia. These prey items closely match what the fish eat in the wild — small invertebrates and zooplankton near the water’s surface and mid-column.
Feed small amounts twice a day. Their stomachs are tiny and overfeeding quickly degrades water quality in a small tank. Remove uneaten food if it is not consumed within a couple of minutes.
Are Chili Rasboras aggressive — and what fish can live with them?
Chili rasboras are fully peaceful and pose no threat to any tank mate. The compatibility challenge runs the other direction: at 2 cm (under an inch), almost anything with a mouth large enough will eat them, and even fish that would not deliberately prey on them may stress or outcompete them for food. Their temperament also means they will not thrive alongside boisterous or nippy species — they will simply hide and fade.
Ideal companions are other nano species with a similarly gentle disposition: ember tetras, sparkling gouramis, pygmy corydoras, small livebearers, and celestial pearl danios all work well at similar size ranges. Dwarf shrimp — neocaridina and caridina varieties — are excellent tank mates and will share the fine-leaved plants without conflict. Avoid any fish over roughly 4 cm (1.5 in) or any species with a history of fin-nipping or aggression.
For a more detailed breakdown of compatible species and species to avoid, see the full Chili Rasbora tank mates guide.
How do you tell male and female Chili Rasboras apart?
Sexual dimorphism in chili rasboras is subtle but consistent once you know what to look for. Males are noticeably more intensely red — particularly on the body and the fin margins — and their colouration intensifies further when displaying to rivals or courting a female. Females are slightly plumper across the belly, especially when carrying eggs, and their overall colouration is paler and more washed-out by comparison.
In a healthy, well-conditioned group the males will frequently display to each other with spread fins and heightened colour, which makes sexing straightforward. In stressed or underconditioned fish both sexes can appear pale, making the distinction harder to read.
How do Chili Rasboras breed?
Breeding chili rasboras is achievable but rated hard for good reason. They scatter small, adhesive eggs among fine-leaved plants or java moss and provide no parental care — and they will readily eat their own eggs and fry. Success requires removing adults after spawning, or using a breeding mesh that lets eggs fall out of reach.
Conditioning the pair or group on live foods (baby brine shrimp, micro worms) for one to two weeks before attempting a spawn tends to increase egg production and female receptiveness. A dedicated breeding tank of 10–15 L (2.5–4 gal), very soft and acidic water (pH 5.5–6.5), subdued lighting, and a thick clump of java moss or spawning mops gives the best chance. Eggs hatch in about 24 hours and the fry are extremely small — infusoria or commercial fry foods suitable for mouth sizes under 100 microns are necessary before they can take newly hatched brine shrimp nauplii. Raising a decent yield of fry to juvenile size is genuinely demanding and requires pristine water and frequent small feeds.
What are common Chili Rasbora diseases?
Chili rasboras are not especially disease-prone when kept in good conditions, but their small size means they decline quickly once illness takes hold. The most common problems are:
Ich (white spot disease): Fine white spots resembling salt grains on the body and fins, often triggered by temperature fluctuation or stress from new arrivals. Raising temperature carefully within the species’ range and reducing stress are the first steps.
Velvet: A dusty gold or rust-coloured sheen on the body, caused by the parasite Oodinium. Often mistaken for colouration initially; fish will scratch against surfaces and show clamped fins.
Bacterial infections and fin deterioration: Usually secondary to water-quality lapses — elevated ammonia, nitrite or nitrate — or physical injury. Maintaining good filtration and performing regular partial water changes (around 20–30% weekly) is the most reliable prevention.
Wasting / internal parasites: Occasionally seen in wild-caught stock; fish lose condition despite eating. Quarantine all new fish before introducing them to the display tank.
Health note: symptoms of many fish diseases overlap significantly. Confirm a diagnosis against a reputable veterinary or aquatic-health resource before beginning any treatment course.
How long do Chili Rasboras live?
In good conditions, chili rasboras live 3–5 years. That lifespan is achievable with stable, soft water, a varied diet, and a stress-free environment with appropriate tank mates and a large enough shoal. Keep at least eight together — smaller groups produce visibly more timid, paler fish that rarely hit their potential lifespan. A thriving colony in a mature blackwater nano tank, regularly topped up with micro foods and given consistent water maintenance, will reward you with years of vivid colour and active schooling behaviour.
Frequently asked questions
Can chili rasboras live with other fish?
Yes, but choose tank mates carefully. Their tiny size (2 cm) makes them vulnerable to any fish large enough to eat them. Best partners are other peaceful nano fish — ember tetras, pygmy corydoras, small livebearers — and dwarf shrimp, which are safe companions. Avoid anything over about 4 cm that might view them as food.
Do chili rasboras need very soft, acidic water?
Ideally yes. In the wild they live in tannin-rich blackwater with very low hardness and pH around 4–5, but aquarium-raised stock adapts to conditions up to pH 7.0 and moderate softness. Adding Indian almond leaves or a small amount of peat will deepen their colour and encourage natural behaviour. Avoid hard, alkaline water — they won't thrive long-term.
What you need to keep a chili rasbora
The baseline is a heated, filtered 20 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a chili rasbora in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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