Photo: Atulbhats (CC BY-SA 4.0) — via Wikimedia Commons
Dwarf Spotted Rasbora (Boraras maculatus)
One of the world's tiniest aquarium fish: a dazzling micro-schooler with bold black spots, perfect for planted nano tanks.
Will it live with a Dwarf Spotted Rasbora?
We compare each fish against your dwarf spotted 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 23–26 °C — no size, zone or temperament conflicts.
- Keep Dwarf Spotted 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 23–26 °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 Dwarf Spotted 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 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Dwarf Spotted 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; 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 Dwarf Spotted 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Dwarf Spotted 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 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 Dwarf Spotted 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.
- 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 Dwarf Spotted 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)
- Compatible on the things that matter: shared water near 23–24 °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 Dwarf Spotted 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.
- Endler's Livebearer✅ CompatiblePeaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Dwarf Spotted 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.
- Exclamation Point Rasbora✅ CompatiblePeaceful · 2 cm · Medium care · 22–28 °C (72–82 °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 Dwarf Spotted 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 23–26 °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 Dwarf Spotted 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 Dwarf Spotted 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)
- 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 Dwarf Spotted 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.
- 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 Dwarf Spotted 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 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Dwarf Spotted 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)
- Both are peaceful, and their water overlaps around 23–26 °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 Dwarf Spotted 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 Dwarf Spotted 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 Dwarf Spotted 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 23–28 °C — no size, zone or temperament conflicts.
- Keep Dwarf Spotted 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 Dwarf Spotted 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 23–28 °C — no size, zone or temperament conflicts.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Tail-spot Corydoras✅ CompatiblePeaceful · 3 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 Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Tail-spot Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Tiger Shrimp✅ CompatiblePeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 23–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ or it gets stressed and nippy.
- Trinidad Guppy✅ CompatiblePeaceful · 3 cm · Easy care · 19–24 °C (66–75 °F)
- Compatible on the things that matter: shared water near 23–24 °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 Dwarf Spotted Rasbora in a shoal of 8+ 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 Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Watch for Black Darter Tetra picking off any dwarf spotted rasbora small enough to fit in its mouth.
- Keep Dwarf Spotted 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 Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Dwarf Spotted Rasbora is small enough to tempt Black Ruby Barb; only risk it in a densely planted setup with hiding spots.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Spotted 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 Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Dwarf Spotted Rasbora is small enough to tempt Black Skirt Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Dwarf Spotted 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 Dwarf Spotted 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 Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Dwarf Spotted Rasbora is small enough to tempt Desert Goby; only risk it in a densely planted setup with hiding spots.
- Keep Dwarf Spotted 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 Dwarf Spotted 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.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Humpbacked Tetra is semi-aggressive and may chase or nip the smaller Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Dwarf Spotted Rasbora is small enough to tempt Humpbacked Tetra; only risk it in a densely planted setup with hiding spots.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ 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 Dwarf Spotted 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.
- Pea Puffer⚠️ With cautionSemi-aggressive · 2.5 cm · Medium care · 24–28 °C (75–82 °F)
- Pea Puffer and Dwarf Spotted Rasbora are close in size, but the semi-aggressive one tends to dominate — add dwarf spotted rasbora in a group to spread the pressure.
- Keep Dwarf Spotted 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 and Dwarf Spotted Rasbora are close in size, but the semi-aggressive one tends to dominate — add dwarf spotted rasbora in a group to spread the pressure.
- Keep Dwarf Spotted 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.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Expect Serpae Tetra to harass Dwarf Spotted Rasbora at times; give dense cover and watch them at feeding.
- Keep Dwarf Spotted 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 Dwarf Spotted Rasbora at times; give dense cover and watch them at feeding.
- Dwarf Spotted Rasbora is small enough to tempt Silvertip Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Dwarf Spotted 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.
- Spotfin Betta⚠️ With cautionSemi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Spotfin Betta is semi-aggressive and may chase or nip the smaller Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Watch for Spotfin Betta picking off any dwarf spotted rasbora small enough to fit in its mouth.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Striped Red-Eye Puffer is aggressive and may chase or nip the smaller Dwarf Spotted Rasbora — plant heavily and break up sight lines.
- Watch for Striped Red-Eye Puffer picking off any dwarf spotted rasbora small enough to fit in its mouth.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Tiger Badis clearly outsizes Dwarf Spotted Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Watch for Tiger Badis picking off any dwarf spotted rasbora small enough to fit in its mouth.
- Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Wine Red Betta⚠️ With cautionAggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Wine Red Betta clearly outsizes Dwarf Spotted Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Wine Red Betta may hunt Dwarf Spotted Rasbora, fry or shrimplets — safest in a heavily planted tank.
- Keep Dwarf Spotted 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)
- Size gap is too large (250 vs 2.5 cm): Alligator Gar will treat Dwarf Spotted Rasbora as food.
- Alligator Gar is aggressive and may chase or nip the smaller Dwarf Spotted 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 Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
- Clown Knifefish clearly outsizes Dwarf Spotted Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Spotted 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 2.5 cm): Fire Eel will treat Dwarf Spotted Rasbora as food.
- Expect Fire Eel to harass Dwarf Spotted 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 Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 90 cm koi — it will be eaten.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Redtail Catfish clearly outsizes Dwarf Spotted Rasbora and is aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Spotted Gar clearly outsizes Dwarf Spotted 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 Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Wels Catfish clearly outsizes Dwarf Spotted 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 Dwarf Spotted 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)
- Dwarf Spotted Rasbora is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
- Wolf Cichlid clearly outsizes Dwarf Spotted 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 Dwarf Spotted 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.
Dwarf Spotted Rasbora care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 2.5 cm (1 in)
- Min tank size
- 40 L (10.6 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 5.5–7
- Hardness
- 1–10 dGH
- Lifespan
- 3–5 years
- Diet
- Carnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Danionidae
- Origin
- Southeast Asia — Malay Peninsula, Singapore, Sumatra (slow, tannin-stained forest streams and peat swamps)
What is a Dwarf Spotted Rasbora?
The dwarf spotted rasbora (Boraras maculatus) is one of the smallest fish kept in the freshwater hobby, reaching a maximum of just 2.5 cm (1 in) at full size. Despite that tiny frame, it earns its place in any planted nano setup through sheer visual impact: a translucent orange-red body is punctuated by three crisp black spots — one behind the gill cover, one on the mid-flank, and one at the base of the dorsal fin — creating a jewel-like effect when a shoal of eight or more moves together against green foliage.
B. maculatus belongs to the genus Boraras, a group of Southeast Asian micro-cyprinids that are closely related to the larger rasboras but deserve their own recognition for their specialist care needs. This is not a fish you drop into any community tank. It comes from some of the most chemically extreme freshwater habitats on Earth — blackwater peat swamps where the water is deeply tannin-stained, almost tea-coloured, with a pH that can fall well below 6.0 and hardness values near zero. Matching those conditions is what separates a thriving colony from a group that fades and dies within months.
Where does the Dwarf Spotted Rasbora come from?
The species is native to Southeast Asia, with the core range spanning the Malay Peninsula (including Singapore) and the Indonesian island of Sumatra. Its preferred habitats are slow-moving or near-stagnant forest streams, swamp margins, and peat bogs — environments defined by heavy shade from the rainforest canopy, thick leaf litter on the substrate, and water coloured deep amber by decaying organic matter.
These blackwater habitats are extremely soft and acidic. Humic and fulvic acids leached from decomposing leaves drive the pH down and keep mineral content minimal. There is essentially no hardness in the water, very little ambient light reaches the water surface through the canopy, and the current is negligible. Understanding this ecology makes every aspect of the care requirements logical: B. maculatus is not a “tough” fish adapted to variable conditions — it is a specialist built for one very specific kind of water.
What tank size and setup does the Dwarf Spotted Rasbora need?
A minimum of 40 litres (about 10 gallons) is the practical floor for a group of this species. This gives enough volume to buffer water parameters and enough horizontal swimming room for a shoal of at least eight fish, which is the minimum group size needed to produce natural behaviour. Longer, shallower tanks are preferable to tall ones — B. maculatus occupies the middle of the water column and benefits from swimming length.
For decoration, aim to replicate the blackwater forest floor. A dark, fine substrate — black sand or a soil substrate — makes the fish’s colouration pop and reduces stress from light reflecting off pale gravel. Cover the base with a layer of dried Indian almond or oak leaves; these slowly release tannins and humic acids that acidify the water gently and naturally. Driftwood and tangles of branching roots add structure. Dense planting with species that thrive in low light and soft water — Java fern, mosses, cryptocorynes, and floating plants to diffuse surface light — completes the environment.
Filtration should produce a slow, gentle current. A small sponge filter is ideal: it provides biological filtration without creating turbulent flow, does not suck in fish too small to escape the intake, and adds surface movement for gas exchange without blasting the shoal around the tank.
What water parameters does the Dwarf Spotted Rasbora need?
- Temperature: 23–28 °C (73–82 °F). The species tolerates a reasonable range, but stability is more important than hitting a precise number.
- pH: 5.5–7.0. Aim for the lower half of this range — pH 6.0–6.5 is closer to wild conditions and produces the best colour.
- Hardness: 1–10 dGH, ideally below 5 dGH. This is the most critical and most commonly misjudged parameter.
For most keepers, meeting the hardness requirement means using reverse-osmosis (RO) water or collected rainwater, then blending it up slightly with a small amount of tap water or a remineraliser to add trace minerals. Straight tap water in the majority of regions is far too hard and alkaline. Adding Indian almond leaves and driftwood helps with pH but does nothing significant to lower hardness — the source water must be right before any of the other measures matter.
Weekly partial water changes of around 20–25% are advisable, replacing with pre-prepared soft, acidic water at the correct temperature.
What do Dwarf Spotted Rasboras eat?
B. maculatus is a carnivore with an extremely small mouth. Standard community fish foods — medium pellets, most flakes — are too large for it to ingest. The diet must consist of appropriately sized, protein-rich items.
Good staple foods include micro-worms, baby brine shrimp (newly hatched nauplii), vinegar eels, and commercially prepared micro-pellets specifically sized for nano fish. Variety matters: rotate in frozen or live daphnia, cyclops, and infusoria to ensure a complete nutritional profile and stimulate natural feeding behaviour. The fish feed primarily in the middle of the water column, picking at items as they drift slowly downward; broadcast feeding in small amounts a couple of times a day suits their natural style. Avoid overfeeding — in a soft-water, low-pH tank, organic waste can destabilise water chemistry rapidly.
How do Dwarf Spotted Rasboras behave, and what fish can live with them?
B. maculatus is entirely peaceful and poses no threat to any tank-mate. The concern runs in the other direction: its diminutive size — no larger than a standard blueberry — means that almost any fish over 5–6 cm (2 in) is a potential predator, even species labelled “peaceful.” The fish must be housed only with companions that are clearly too small to view it as prey and gentle enough not to outcompete it at feeding time.
Within a species-only setup or a carefully assembled micro-community, the shoaling behaviour is captivating. A group of eight or more will cruise together through the midwater, occasionally splitting and reforming, with the red and black markings flashing as they turn in and out of the light. Groups smaller than eight tend to be skittish, hiding more and showing less colour.
Proven compatible tank-mates in a blackwater nano include: pygmy corydoras (Corydoras pygmaeus or C. hastatus), ember tetras (Hyphessobrycon amandae), chili rasboras (Boraras brigittae), sparkling gourami (Trichopsis pumila), and otocinclus catfish. Small, non-predatory shrimp such as crystal red or black shrimp can coexist, though any shrimp small enough to fit in a fish’s mouth carries some risk.
For a detailed, filterable breakdown of what works, see Dwarf Spotted Rasbora tank mates.
How do you tell male from female Dwarf Spotted Rasboras?
Sexual dimorphism in B. maculatus is subtle but visible to an experienced eye. Females are slightly deeper-bodied — particularly noticeable when ripe with eggs, when the belly becomes visibly rounded — and are marginally larger overall. Males are slimmer in profile and tend to display more intense red colouration on the body, which becomes especially vivid when fish are in breeding condition or competing for a female’s attention. The difference is most obvious when comparing multiple individuals side by side in good light. Young fish are nearly impossible to sex reliably; wait until the fish are several months old.
Can you breed Dwarf Spotted Rasboras?
Breeding is possible but rated hard, reflecting the precision the process demands. The fish scatter eggs among fine-leaved plants and moss, with no parental guarding — parents and other tank residents will eat eggs given the opportunity. A separate, small breeding tank (15–20 litres) conditioned with Java moss or spawning mops, soft acidic water, very dim light, and a well-fed pair or small group is the standard approach.
Condition adults with varied live foods for several weeks before attempting spawning. The female will scatter small, semi-adhesive eggs among the plants; remove adults after spawning is observed. Eggs hatch in around 24–48 hours depending on temperature, and the fry are extremely small — one of the smallest in the hobby. First foods must be appropriately tiny: infusoria, rotifers, or commercial first-fry foods, with baby brine shrimp nauplii introduced only once the fry are large enough to take them. Water quality and temperature stability during the fry stage are critical.
What diseases affect Dwarf Spotted Rasboras?
The most common disease problems are ich (Ichthyophthirius multifiliis), presenting as white salt-grain spots across the body and fins, and velvet (Oodinium spp.), which appears as a fine gold or rust-coloured dusting. Both are almost always introduced with new fish or plants and thrive when fish are stressed by poor water conditions. Bacterial infections — shown as fin fraying, ulcers, or redness — can also develop in tanks with deteriorating water quality.
Prevention is simpler than cure for a species as small and water-quality-dependent as this one. A strict quarantine protocol for all new fish (a minimum of three to four weeks in a separate tank) prevents pathogen introduction. Maintaining stable, correct water parameters — particularly pH and softness — keeps the fish’s immune system functioning. Avoid sudden temperature drops and abrupt water-parameter swings, which are significant stress triggers. Routine siphoning of detritus from the substrate and regular partial water changes remove the organic load that fuels bacterial growth.
Health note: medication dosing and disease diagnosis are beyond the scope of a care profile. Treatments safe for standard community fish can be toxic to very small micro-cyprinids at normal doses. For sick fish, confirm the diagnosis carefully and consult a reputable aquatic veterinary or fish-health resource before medicating.
How long do Dwarf Spotted Rasboras live?
A well-maintained B. maculatus can live 3–5 years. This lifespan is achievable in captivity when the soft, acidic water requirements are met consistently and the fish are kept in an appropriate group. Fish housed in incorrect water chemistry — too hard, too alkaline, or too variable — typically show faded colour, reduced activity, and a significantly shortened lifespan. Given that they are sometimes sold as adults of uncertain age, buying from a reputable source and getting the setup right from day one gives the best chance of seeing the full span of those years.
Frequently asked questions
Can dwarf spotted rasboras live with other fish?
Yes, but choose tank-mates very carefully given their tiny size. Safe companions are similarly small and peaceful blackwater species — pygmy corydoras, ember tetras, sparkling gourami, otocinclus, and small Apistogramma species. Any fish large or boisterous enough to mistake them for food must be avoided.
Why are dwarf spotted rasboras harder to keep than other rasboras?
Their main demands are soft, acidic water and a mature, well-planted tank. Tap water in most regions is too hard and too alkaline, so keepers usually need RO water or rainwater blended down to the correct parameters. Once the tank is set up correctly they are straightforward — it's the water chemistry that trips people up.
What you need to keep a dwarf spotted rasbora
The baseline is a heated, filtered 40 L+ tank: a reliable heater to hold 23–28 °C (73–82 °F), a gentle filter that won't batter a dwarf spotted rasbora in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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