Photo: R.workoran (CC BY-SA 4.0) — via Wikimedia Commons
Exclamation Point Rasbora (Boraras urophthalmoides)
A tiny, jewel-toned nano fish whose bold caudal eyespot makes every planted tank look like a living painting.
Will it live with a Exclamation Point Rasbora?
We compare each fish against your exclamation point 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Exclamation Point 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, 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 Exclamation Point 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)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Exclamation Point 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.
- Chili Rasbora✅ CompatiblePeaceful · 2 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °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 Exclamation Point Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Chili Rasbora in a shoal of 8+ 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 Exclamation Point 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)
- 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 Exclamation Point 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 Exclamation Point 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)
- 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 Exclamation Point 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, and their water overlaps around 22–24 °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 Exclamation Point 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.
- 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 Exclamation Point 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; 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 Exclamation Point 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; 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 Exclamation Point 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)
- Compatible on the things that matter: shared water near 22–27 °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 Exclamation Point 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)
- 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 Exclamation Point 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 Exclamation Point 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 Exclamation Point 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)
- Compatible on the things that matter: shared water near 22–26 °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 Exclamation Point 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 Exclamation Point 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)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Keep Exclamation Point 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)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Exclamation Point 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 Exclamation Point 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 Exclamation Point 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)
- 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 Exclamation Point 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 Exclamation Point 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)
- Expect Black Darter Tetra to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Exclamation Point Rasbora is small enough to tempt Black Darter Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Exclamation Point 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)
- Black Ruby Barb is semi-aggressive and may chase or nip the smaller Exclamation Point Rasbora — plant heavily and break up sight lines.
- Black Ruby Barb may hunt Exclamation Point 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 Exclamation Point 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)
- Black Skirt Tetra is semi-aggressive and may chase or nip the smaller Exclamation Point Rasbora — plant heavily and break up sight lines.
- Black Skirt Tetra may hunt Exclamation Point Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Exclamation Point 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)
- Different pH ranges (5.5–7 vs 7.5–8.5); doable if you sit in the shared band, but not ideal long-term.
- Keep Exclamation Point 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)
- Expect Desert Goby to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Desert Goby may hunt Exclamation Point Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Exclamation Point 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 Exclamation Point 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)
- Water hardness preferences differ (Exclamation Point Rasbora 1–8 vs Endler's Livebearer 10–25 dGH).
- Keep Exclamation Point 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)
- Expect GloFish Tetra to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- GloFish Tetra may hunt Exclamation Point Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Exclamation Point 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 Exclamation Point 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)
- Odessa Barb clearly outsizes Exclamation Point Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Exclamation Point Rasbora is small enough to tempt Odessa Barb; only risk it in a densely planted setup with hiding spots.
- Keep Exclamation Point 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 and Exclamation Point Rasbora are close in size, but the semi-aggressive one tends to dominate — add exclamation point rasbora in a group to spread the pressure.
- Keep Exclamation Point 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 is semi-aggressive and may chase or nip the smaller Exclamation Point Rasbora — plant heavily and break up sight lines.
- Watch for Rainbow Emperor Tetra picking off any exclamation point rasbora small enough to fit in its mouth.
- Keep Exclamation Point 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 and Exclamation Point Rasbora are close in size, but the semi-aggressive one tends to dominate — add exclamation point rasbora in a group to spread the pressure.
- Keep Exclamation Point 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)
- Serpae Tetra is semi-aggressive and may chase or nip the smaller Exclamation Point Rasbora — plant heavily and break up sight lines.
- Serpae Tetra may hunt Exclamation Point Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Exclamation Point 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)
- Expect Silvertip Tetra to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Watch for Silvertip Tetra picking off any exclamation point rasbora small enough to fit in its mouth.
- Keep Exclamation Point 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)
- Expect Tiger Badis to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Exclamation Point Rasbora is small enough to tempt Tiger Badis; only risk it in a densely planted setup with hiding spots.
- Keep Exclamation Point 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 Exclamation Point Rasbora whole.
- Expect Alligator Gar to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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)
- Exclamation Point 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 Exclamation Point 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 Exclamation Point 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)
- Size gap is too large (100 vs 2 cm): Fire Eel will treat Exclamation Point Rasbora as food.
- Fire Eel clearly outsizes Exclamation Point Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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)
- Size gap is too large (90 vs 2 cm): Koi will treat Exclamation Point Rasbora as food.
- Water hardness preferences differ (Exclamation Point Rasbora 1–8 vs Koi 9–18 dGH).
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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 Exclamation Point Rasbora as food.
- Expect Redtail Catfish to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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)
- Exclamation Point Rasbora is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Spotted Gar is aggressive and may chase or nip the smaller Exclamation Point Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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)
- Size gap is too large (300 vs 2 cm): Wels Catfish will treat Exclamation Point Rasbora as food.
- Wels Catfish clearly outsizes Exclamation Point Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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)
- Size gap is too large (72 vs 2 cm): Wolf Cichlid will treat Exclamation Point Rasbora as food.
- Expect Wolf Cichlid to harass Exclamation Point Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Exclamation Point 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.
Exclamation Point Rasbora care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 2 cm (0.8 in)
- Min tank size
- 30 L (7.9 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 5.5–7
- Hardness
- 1–8 dGH
- Lifespan
- 3–5 years
- Diet
- Carnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Danionidae
- Origin
- Southeast Asia — Thailand, Cambodia, Laos (lowland peat swamps and blackwater streams)
What is an Exclamation Point Rasbora?
The exclamation point rasbora (Boraras urophthalmoides) is one of the smallest fish in the aquarium hobby, topping out at 2 cm (0.8 in). Despite that size, it is a striking animal: a semi-translucent body set off by a bold black-and-gold caudal eyespot and red-orange fin accents. In a tannin-stained planted tank, a school of eight or more becomes something genuinely special — a living mobile of colour and movement that no larger fish can replicate at nano scale.
The species belongs to Boraras, the true dwarf rasboras of lowland Southeast Asia. It is closely related to the chili rasbora (Boraras brigittae) and the phoenix rasbora (Boraras merah); all three can be confused in store tanks. B. urophthalmoides is distinguished by the spot-and-dash pattern on the flank that gives it the exclamation-point name.
Where do Exclamation Point Rasboras come from?
Wild populations span the lowland drainages of Thailand, Cambodia and Laos — slow peat swamp forests and shaded blackwater streams. The water there is amber-stained by decomposing leaf litter, extremely soft (as low as 1 dGH), acidic (pH well below 6 in some localities), and warm, sitting in the 22–28 °C (72–82 °F) range. Fish moved from bright, alkaline store water into a properly conditioned blackwater tank will colour up and school naturally in a way that never happens in hard, neutral conditions. The habitat is the care template.
What size tank does an Exclamation Point Rasbora need?
Thirty litres (8 US gal) is the practical minimum, assuming a cycled tank with gentle filtration and dense planting. The tank does not need to be large in absolute terms, but it must be stable and mature. Longer, shallower footprints suit this mid-column swimmer better than tall designs. A 60 cm aquascape with dark substrate, driftwood and a mix of floating and rooted plants hits the brief perfectly. Sponge filters or diffused canister outlets keep flow gentle enough that the fish aren’t pushed around. Fit a lid — small rasboras jump when startled.
What water parameters do Exclamation Point Rasboras need?
- Temperature: 22–28 °C (72–82 °F). The midpoint of around 25 °C suits them well year-round.
- pH: 5.5–7.0. Aim for the soft-acid end of that range — 6.0–6.5 — for best colour and breeding condition.
- Hardness: 1–8 dGH. This is a genuinely soft-water species; hard tap water needs conditioning or blending with RO water.
Indian almond leaves, alder cones, or peat filtration are optional but noticeably improve colour by replicating blackwater tannins. Consistency matters more than chasing perfect numbers: a tank parked at pH 6.2 every day outperforms one that swings between 6.0 and 7.5 through inconsistent water changes. Cycle thoroughly before adding fish, and top up with soft, temperature-matched water on a regular schedule.
What do Exclamation Point Rasboras eat?
In the wild, B. urophthalmoides picks off tiny crustaceans, worm larvae and zooplankton. Their small mouths mean standard flake and medium pellets are poorly sized; food needs to fit a 2 cm fish. Feed a rotation of:
- Prepared: quality nano pellets, micro-granules, finely crushed high-protein flake.
- Live/frozen: baby brine shrimp nauplii, micro worms, Moina, daphnia.
Offer small amounts two or three times daily. Siphon uneaten food promptly — small tanks foul quickly. A varied, live-food-supplemented diet also conditions adults for breeding.
Are Exclamation Point Rasboras peaceful — and what fish can live with them?
Boraras urophthalmoides is entirely peaceful. The risk runs in the opposite direction: at 2 cm (0.8 in), they are potential prey for almost any fish with a mouth large enough to swallow them. Ideal tankmates are similarly tiny and gentle — other Boraras species, pygmy corydoras (C. pygmaeus or C. habrosus), ember tetras, small otocinclus and adult dwarf shrimp. Avoid any fish over roughly 4–5 cm that is not confirmed safe around nano fish.
Within their own group, the minimum of 8 individuals is important: smaller numbers produce nervous, pale fish that hide. Groups of 12 or more display the confident, tight shoaling behaviour that makes the species worth keeping.
For a full breakdown of compatible species, see Exclamation Point Rasbora tank mates.
How do you tell male from female Exclamation Point Rasboras?
Sexing requires conditioned adults and a close look. Females are slightly larger and noticeably fuller when gravid — a ripe female’s abdomen is clearly rounded compared to the slimmer male. Males compensate in colour: more intense red-orange in the fins and a crisper eyespot. Outside breeding condition the differences are subtle. A group of eight or more will typically contain both sexes; differences become obvious once the fish settle in and females begin filling with eggs.
How do Exclamation Point Rasboras breed?
Breeding is rated hard — not because the fish are fragile, but because the conditions required to trigger spawning are exacting and the fry demand precision feeding. Condition males and females separately for 1–2 weeks on live micro foods, then introduce them to a dedicated 10–20 L spawning tank with very soft, acidic water (pH ~6.0, hardness below 4 dGH), java moss or fine-leaved plants, and dim lighting.
Spawning is an egg-scatter: the pair releases small numbers of eggs among plants, then will eat them. Use a mesh bottom so eggs fall away from adults, or remove the adults after spawning. Eggs hatch in 24–36 hours at 26 °C. Fry are minuscule and need infusoria or commercial first foods for several days before accepting baby brine shrimp nauplii. They are slow-growing and require pristine water. Success is achievable with patience, but this is not a beginner project.
What diseases affect Exclamation Point Rasboras?
Boraras urophthalmoides is no more disease-prone than other small cyprinids, but its tiny size means that by the time visible symptoms appear, the fish may already be in serious decline. Early detection and prevention are therefore especially important.
The most common issues are:
- Ich (white spot): Fine white grains across the body, caused by temperature drops or stress from inadequate acclimation. Prevented by stable temperatures and proper quarantine of new arrivals.
- Velvet (Oodinium): A dusty, gold-toned sheen on the fins and body; often introduced with new fish. Quarantine is the principal defence.
- Bacterial infections / fin damage: Usually a water-quality problem. Keep ammonia and nitrite at zero and nitrate low through regular water changes.
- Intestinal parasites: May occur in wild-caught specimens. Quarantine and observation before introduction to a display tank catch most cases.
Health note: at 2 cm, B. urophthalmoides is extremely sensitive to medication overdose. Medication dosing and disease diagnosis are beyond the scope of this care profile — for a sick fish, confirm the diagnosis against a reputable fish-health resource and scale any treatment carefully to tank volume and fish size before proceeding.
How long do Exclamation Point Rasboras live?
A well-kept exclamation point rasbora lives 3–5 years — a respectable lifespan for a 2 cm fish. Hard, alkaline water or a poor diet pushes fish toward the lower end; a mature blackwater setup with a live-food-supplemented diet routinely reaches the upper range. Wild-caught specimens arrive at unknown age, so focus on what you can control: stable soft water, a proper group size and appropriately sized food. Get those right and these tiny fish will reward you with years of colour and movement.
Frequently asked questions
Can exclamation point rasboras live with bettas?
Sometimes — a large, heavily planted tank with a single peaceful male betta can work, since both fish share soft, acidic water preferences. However, the rasboras' tiny size and the betta's individual personality make this a calculated risk: observe closely and have a backup plan.
Why are they called exclamation point rasboras?
The name comes from the black caudal spot paired with a short dark dash just in front of it on the flank — together they resemble an exclamation mark. The pattern is most vivid in well-conditioned fish kept in soft, tannin-stained water.
What you need to keep a exclamation point rasbora
The baseline is a heated, filtered 30 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a exclamation point rasbora in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
As an Amazon Associate we earn from qualifying purchases — buying through these links costs you nothing extra.
