Photo: Cantospira (CC BY-SA 4.0) — via Wikimedia Commons
Emerald Dwarf Danio (Danio erythromicron)
A jewel-sized nano danio from Myanmar's Inle Lake — iridescent teal stripes and fiery red-orange fins packed into just 2 cm of fish.
Will it live with a Emerald Dwarf Danio?
We compare each fish against your emerald dwarf danio 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 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Emerald Dwarf Danio 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 22–24 °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 Emerald Dwarf Danio 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 20–24 °C — no size, zone or temperament conflicts.
- Keep Emerald Dwarf Danio 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 22–24 °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 Emerald Dwarf Danio 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.
- Dawn Tetra✅ CompatiblePeaceful · 2.5 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–24 °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 Emerald Dwarf Danio 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)
- Both are peaceful, and their water overlaps around 23–24 °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 Emerald Dwarf Danio 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 24–24 °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 Emerald Dwarf Danio 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.
- Endler's Livebearer✅ CompatiblePeaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Emerald Dwarf Danio 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; 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 Emerald Dwarf Danio 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)
- Compatible on the things that matter: shared water near 22–24 °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 Emerald Dwarf Danio 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 20–24 °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 Emerald Dwarf Danio 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.
- Hummingbird Tetra✅ CompatiblePeaceful · 1.8 cm · Hard care · 22–27 °C (72–81 °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 Emerald Dwarf Danio 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 Emerald Dwarf Danio 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)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Emerald Dwarf Danio in a shoal of 8+ 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 Emerald Dwarf Danio 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)
- Compatible on the things that matter: shared water near 20–24 °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 Emerald Dwarf Danio 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Emerald Dwarf Danio 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, and their water overlaps around 20–24 °C — no size, zone or temperament conflicts.
- Keep Emerald Dwarf Danio 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Ruby Tetra✅ CompatiblePeaceful · 2 cm · Medium care · 23–28 °C (73–82 °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 Emerald Dwarf Danio 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 23–24 °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 Emerald Dwarf Danio 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.
- Tail-spot Corydoras✅ CompatiblePeaceful · 3 cm · Easy care · 22–28 °C (72–82 °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 Emerald Dwarf Danio 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)
- Both are peaceful, and their water overlaps around 20–24 °C — no size, zone or temperament conflicts.
- Keep Emerald Dwarf Danio 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 20–24 °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 Emerald Dwarf Danio 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)
- Different pH ranges (7–8 vs 3.5–6.5); doable if you sit in the shared band, but not ideal long-term.
- Expect Black Darter Tetra to harass Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Emerald Dwarf Danio is small enough to tempt Black Darter Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Emerald Dwarf Danio 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 Emerald Dwarf Danio — plant heavily and break up sight lines.
- Watch for Black Ruby Barb picking off any emerald dwarf danio small enough to fit in its mouth.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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.
- Crimson Red Betta⚠️ With cautionPeaceful · 3.5 cm · Hard care · 24–29 °C (75–84 °F)
- pH preferences only just meet (Emerald Dwarf Danio 7–8 vs Crimson Red Betta 4–6.5) — target the overlap and acclimate slowly.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Crystal Red Shrimp⚠️ With cautionPeaceful · 2.5 cm · Hard care · 20–24 °C (68–75 °F)
- pH preferences only just meet (Emerald Dwarf Danio 7–8 vs Crystal Red Shrimp 6–6.8) — target the overlap and acclimate slowly.
- Keep Emerald Dwarf Danio 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.
- Fire Red Licorice Gourami⚠️ With cautionPeaceful · 3.5 cm · Hard care · 23–28 °C (73–82 °F)
- pH preferences only just meet (Emerald Dwarf Danio 7–8 vs Fire Red Licorice Gourami 4–6.5) — target the overlap and acclimate slowly.
- One likes softer water and the other harder (5–12 vs 0–4 dGH) — a compromise, not a perfect match.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Green Neon Tetra⚠️ With cautionPeaceful · 2.5 cm · Hard care · 24–28 °C (75–82 °F)
- Different pH ranges (7–8 vs 4.5–6.5); doable if you sit in the shared band, but not ideal long-term.
- Water hardness preferences differ (Emerald Dwarf Danio 5–12 vs Green Neon Tetra 0–4 dGH).
- Keep Emerald Dwarf Danio 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.
- 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 Emerald Dwarf Danio 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.
- Neon Blue Rasbora⚠️ With cautionPeaceful · 2.5 cm · Medium care · 23–26 °C (73–79 °F)
- pH preferences only just meet (Emerald Dwarf Danio 7–8 vs Neon Blue Rasbora 4–6.5) — target the overlap and acclimate slowly.
- Keep Emerald Dwarf Danio 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.
- Pea Puffer⚠️ With cautionSemi-aggressive · 2.5 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Pea Puffer to harass Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Purple Tetra⚠️ With cautionPeaceful · 4 cm · Medium care · 22–26 °C (72–79 °F)
- Different pH ranges (7–8 vs 5.8–6.8); doable if you sit in the shared band, but not ideal long-term.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Purple Tetra 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)
- Expect Rainbow Emperor Tetra to harass Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Emerald Dwarf Danio is small enough to tempt Rainbow Emperor Tetra; only risk it in a densely planted setup with hiding spots.
- Keep Emerald Dwarf Danio 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)
- Expect Scarlet Badis to harass Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Keep Emerald Dwarf Danio 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 Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Serpae Tetra may hunt Emerald Dwarf Danio, fry or shrimplets — safest in a heavily planted tank.
- Keep Emerald Dwarf Danio 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 Emerald Dwarf Danio and is semi-aggressive; risky unless the tank is big and well-planted.
- Silvertip Tetra may hunt Emerald Dwarf Danio, fry or shrimplets — safest in a heavily planted tank.
- Keep Emerald Dwarf Danio 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 clearly outsizes Emerald Dwarf Danio and is semi-aggressive; risky unless the tank is big and well-planted.
- Emerald Dwarf Danio is small enough to tempt Tiger Badis; only risk it in a densely planted setup with hiding spots.
- Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
- Tucano Tetra⚠️ With cautionPeaceful · 1.7 cm · Hard care · 23–28 °C (73–82 °F)
- Different pH ranges (7–8 vs 4.5–6.5); doable if you sit in the shared band, but not ideal long-term.
- Keep Emerald Dwarf Danio 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.
- 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 Emerald Dwarf Danio whole.
- Alligator Gar is aggressive and may chase or nip the smaller Emerald Dwarf Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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)
- Emerald Dwarf Danio 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 Emerald Dwarf Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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)
- Emerald Dwarf Danio is bite-sized to a 100 cm predatory fire eel — it will be eaten.
- Fire Eel is semi-aggressive and may chase or nip the smaller Emerald Dwarf Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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 Emerald Dwarf Danio as food.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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)
- Redtail Catfish (120 cm) is big enough to swallow the 2 cm Emerald Dwarf Danio whole.
- Redtail Catfish is aggressive and may chase or nip the smaller Emerald Dwarf Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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)
- Size gap is too large (90 vs 2 cm): Spotted Gar will treat Emerald Dwarf Danio as food.
- Spotted Gar is aggressive and may chase or nip the smaller Emerald Dwarf Danio — plant heavily and break up sight lines.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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)
- Emerald Dwarf Danio is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Expect Wels Catfish to harass Emerald Dwarf Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Emerald Dwarf Danio 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 Emerald Dwarf Danio as food.
- Expect Wolf Cichlid to harass Emerald Dwarf Danio 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 Emerald Dwarf Danio 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.
Emerald Dwarf Danio care specs
- Care level
- Medium
- Breeding
- Medium
- Max size
- 2 cm (0.8 in)
- Min tank size
- 40 L (10.6 gal)
- Temperature
- 20–24 °C (68–75 °F)
- pH
- 7–8
- Hardness
- 5–12 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Danionidae
- Origin
- Inle Lake and surrounding drainages, Shan State, Myanmar
What is an Emerald Dwarf Danio?
The Emerald Dwarf Danio (Danio erythromicron), long sold under the synonym Microrasbora erythromicron, is one of the most visually striking nano fish available to freshwater aquarists. Adults cap out at around 2 cm (¾ in) — barely the length of a thumbnail — yet they carry a body patterned with vivid teal-green iridescence and a series of vertical orange-red bars running from mid-body to the caudal peduncle. The fins pick up the same fiery accent, and in good light a well-conditioned group shimmers like scattered gemstones against a planted backdrop.
This is a true schooling species that must be kept in meaningful numbers. A group of eight is the practical floor; ten to fifteen is where the fish really come alive. In a correctly sized school, males display almost constantly — fanning fins, chasing, colour-shifting — which makes even a modestly planted 40 L (10 gal) tank a genuinely dynamic display. Fewer than eight individuals produces chronically shy, washed-out fish that spend most of their time hiding in the corners.
Classified as Medium care, the Emerald Dwarf Danio is not a beginner’s fish primarily because of its temperature requirements and sensitivity to high temperatures, but it rewards the keeper who reads its natural history and sets up the tank accordingly.
Where do Emerald Dwarf Danios come from in the wild?
Danio erythromicron is endemic to Inle Lake and its immediate satellite drainages in Shan State, Myanmar — a large, shallow, highland lake that sits above 900 m (2,950 ft) elevation. The lake is characterised by relatively cool water, neutral-to-alkaline chemistry, moderate hardness and excellent clarity, with dense stands of aquatic vegetation and a silty substrate. Seasonal temperatures at Inle average in the low-to-mid twenties Celsius, and the fish have evolved in a window of 20–24 °C (68–75 °F) — meaningfully cooler than most tropical species.
This origin explains nearly every care requirement: cool temperatures, neutral to slightly alkaline and moderately hard water, abundant plant cover and a calm, clear-water environment. In temperate regions, lightly heated or even unheated tanks (depending on ambient room temperature) can suit this species year-round — a genuine advantage for nano aquarists who prefer to run lower-energy setups.
What size tank do Emerald Dwarf Danios need and how should it be set up?
A group of eight Emerald Dwarf Danios requires a minimum of 40 L (10 gal), ideally in a long, shallow footprint (60 cm / 24 in or more in length) that maximises horizontal swimming room. These fish occupy the middle water column and range actively, so surface area matters more than depth.
Planting should be generous. A dense background of fine-leaved plants — Rotala, Myriophyllum, Vallisneria — with some floating cover (hornwort or frogbit) and a few open midwater lanes creates the natural structure they use in the wild. A substrate of fine gravel or inert sand suits them, and a dark-coloured substrate makes the iridescent teal body pop visually. Filtration should produce gentle flow; these fish come from a calm lake environment and will struggle to feed or display in a strong current. A sponge filter or a canister dialled back with a spray bar is ideal. A lid is advisable since danios can jump, though D. erythromicron is less prone to this than some relatives.
What water parameters do Emerald Dwarf Danios need?
- Temperature: 20–24 °C (68–75 °F). This is the single most critical parameter. Extended exposure above 25 °C causes chronic stress, immune suppression and shortened lifespan.
- pH: 7.0–8.0. Neutral to mildly alkaline; reflecting the alkaline chemistry of Inle Lake.
- Hardness: 5–12 dGH. Moderate hardness. Many temperate tapwater supplies fall naturally in this range.
Stability is equally important as the specific values. Cycle the tank fully before adding fish, maintain weekly water changes of around 20–25%, and avoid sudden swings in temperature or chemistry. The Emerald Dwarf Danio’s cool-water preference means checking whether your local tap supply rises seasonally — summer ambient temperatures can push a lightly heated or unheated tank beyond the species’ comfort zone without the keeper noticing.
What do Emerald Dwarf Danios eat?
These fish are omnivores with a preference for small invertebrates and zooplankton in the wild. In the aquarium, a staple of high-quality micro pellets or crushed flake forms the base diet, but the fish colour up and behave most naturally when offered regular variety: frozen or live baby brine shrimp, daphnia, micro worms and cyclops are all accepted eagerly and bring out the most vivid display behaviour in males.
Because adults reach only 2 cm (¾ in), food particle size matters: standard flake and large pellets are too big for them to process efficiently. Micro pellets (0.5–1 mm) or finely crushed flake are appropriate for daily feeding. Feed small amounts once or twice daily — only what the group can consume within a couple of minutes — and siphon any uneaten food promptly to protect water quality in a small tank.
How do Emerald Dwarf Danios behave and what fish can live with them?
The Emerald Dwarf Danio is a peaceful schooling fish with an active, curious disposition. Males engage in near-constant low-level sparring and colour displays within the group, which is entirely benign — it is social communication rather than aggression, and no fish are harmed. The species occupies the middle water column and is generally bold once settled in a large enough group.
Because of their tiny adult size (2 cm / ¾ in), compatible tankmates must be chosen with genuine care. Any fish capable of fitting this species in its mouth is a predator in practice, regardless of how it is labelled on a care sheet. Suitable companions include:
- Celestial Pearl Danios (Danio margaritatus) — same size, similar cool-water preference
- Dwarf or pygmy corydoras (Corydoras pygmaeus, C. hastatus) — peaceful bottom dwellers
- Small, peaceful rasboras of similar size
- Freshwater shrimp (Neocaridina or Caridina) — good microalgae cleaners, generally safe with adults though very small shrimp fry may be picked at
Avoid anything significantly larger, fin-nippers (tiger barbs, serpae tetras), or boisterous schooling fish that will outcompete them at feeding time.
For a full list of tested pairings, see Emerald Dwarf Danio tank mates.
How do you tell male from female Emerald Dwarf Danios apart?
Sexual dimorphism in this species is moderate and becomes clearer once the fish are a few months old and well conditioned. Males are noticeably slimmer in the body, carry more saturated teal iridescence and develop more intensely coloured orange-red vertical bars and fin pigmentation — particularly when actively displaying. Females are fuller-bodied (visibly rounder through the belly when gravid), somewhat paler overall, and their bars tend toward a softer pink-orange rather than deep red.
In a mixed, well-fed group you can usually pick out females by their rounded abdominal profile even when the fish are resting. Colour alone can mislead in poor light or when fish are stressed, so body shape is the more reliable indicator.
How do Emerald Dwarf Danios breed?
Breeding Danio erythromicron in the aquarium is achievable at home but requires some preparation, which is why the species is rated Medium difficulty for breeding.
The species is a scatter spawner with no parental care. Males display intensely to females, and pairs will scatter adhesive eggs among fine-leaved plants and moss. In a heavily planted species-only tank, small numbers of fry will sometimes appear and grow on without intervention — the fine vegetation provides refuges for eggs and newly hatched fry that the adults cannot easily locate. For a deliberate breeding attempt, condition a small group on varied live and frozen foods, provide dense Java moss or similar spawning substrate, and move eggs or adults after spawning to a separate grow-out vessel to prevent predation. Fry are tiny at hatching and require infusoria or very finely powdered first foods before graduating to baby brine shrimp nauplii. Water temperature in the lower end of the range (around 22 °C / 72 °F) and good water quality are the key practical conditions for triggering spawning.
What diseases commonly affect Emerald Dwarf Danios?
Like most small danios, D. erythromicron is susceptible to the standard suite of freshwater diseases when kept in suboptimal conditions:
- Ich (white spot) — the classic white-spot parasite, most likely to appear after temperature drops or the introduction of new fish without quarantine. Raising temperature gradually within range and standard treatment protocols address outbreaks caught early.
- Velvet (Oodinium) — a fine gold-dust coating, harder to spot than ich; look for flashing behaviour (rubbing against surfaces). Dim lighting makes it more visible.
- Bacterial infections / fin fraying — secondary to stress; almost always trace back to poor water quality, overcrowding or a temperature that is chronically too warm.
- Wasting / failure to thrive — in this species this commonly signals either an internal parasite (not uncommon in wild-caught stock) or an incompatible diet of oversized food particles.
The overwhelming majority of health problems are prevented by the same practices: quarantine all new fish for two to four weeks before introduction, maintain a fully cycled tank, keep the temperature within the 20–24 °C (68–75 °F) window, and make regular water changes non-negotiable.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. For a sick fish, confirm the specific pathogen against a reputable veterinary or fish-health reference before selecting or applying any treatment.
How long do Emerald Dwarf Danios live?
With good husbandry, Emerald Dwarf Danios live 3–5 years. For a fish of this size, that is a reasonable lifespan, and it is achievable in practice when the key conditions are met: a cool, stable temperature within their range, appropriate water chemistry, clean water through consistent maintenance, and a large enough group to allow normal social behaviour. Fish kept too warm, in too small a group or in poorly maintained water rarely reach the upper end of that range. Get the fundamentals right and a school of D. erythromicron will remain a vivid, active display for several years.
Frequently asked questions
Can I keep Emerald Dwarf Danios with other nano fish?
Yes, with care. They pair well with other small, peaceful species from similar cool, hard-water environments — such as Celestial Pearl Danios, small rasboras and dwarf corydoras. Avoid tankmates large enough to eat them or boisterous fish that out-compete them for food.
Why do my Emerald Dwarf Danios hide and look pale?
Pale colour and hiding almost always indicate stress from an under-sized group (keep at least eight), a lack of cover, or water temperature that is too warm. This species comes from a cool highland lake — temperatures above 25 °C for extended periods will stress them. Add more individuals, provide floating plants for cover, and check your thermometer.
What you need to keep a emerald dwarf danio
The baseline is a heated, filtered 40 L+ tank: a reliable heater to hold 20–24 °C (68–75 °F), a gentle filter that won't batter a emerald dwarf danio in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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