Northern Glowlight Danio (Danio flagrans)
A rare gem from the mountains of northern Myanmar — fiery red stripes and bold dark bars on a nano fish that demands cool, clean water.
Will it live with a Northern Glowlight Danio?
We compare each fish against your northern glowlight danio on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- African Dwarf Frog✅ CompatiblePeaceful · 4 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.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Amapá Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 24–27 °C (75–81 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
- Blackwing Hatchetfish✅ CompatiblePeaceful · 3.5 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.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Blackwing Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Blue Danio✅ CompatiblePeaceful · 4 cm · Easy care · 21–26 °C (70–79 °F)
- Compatible on the things that matter: shared water near 21–24 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Danio in a shoal of 6+ or it gets stressed and nippy.
- Blue Emperor Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cardinal Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
- Clown Killifish✅ CompatiblePeaceful · 3.5 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.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Crimson Red Betta✅ CompatiblePeaceful · 3.5 cm · Hard care · 24–29 °C (75–84 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Emperor Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Eyespot Rasbora✅ CompatiblePeaceful · 3.5 cm · Medium care · 20–25 °C (68–77 °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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Eyespot Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Fire Red Licorice Gourami✅ CompatiblePeaceful · 3.5 cm · Hard 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Flame Tetra✅ CompatiblePeaceful · 4 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
- Ghost Shrimp✅ CompatiblePeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Compatible on the things that matter: shared water near 18–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Ghost Shrimp in a shoal of 6+ or it gets stressed and nippy.
- Glowlight Rasbora✅ CompatiblePeaceful · 3.5 cm · Easy 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Glowlight Tetra✅ CompatiblePeaceful · 4 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Golden Dwarf Barb✅ CompatiblePeaceful · 4 cm · Easy care · 18–24 °C (64–75 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Golden Dwarf Barb in a shoal of 6+ or it gets stressed and nippy.
- Jelly Bean Tetra✅ CompatiblePeaceful · 4 cm · Medium 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Jelly Bean Tetra in a shoal of 10+ or it gets stressed and nippy.
- Marbled Hatchetfish✅ CompatiblePeaceful · 4 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.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Otocinclus✅ CompatiblePeaceful · 4 cm · Medium care · 21–26 °C (70–79 °F)
- Compatible on the things that matter: shared water near 21–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Phoenix Tetra✅ CompatiblePeaceful · 4 cm · Easy 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
- Purple Tetra✅ CompatiblePeaceful · 4 cm · Medium 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 Northern Glowlight 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.
- Pygmy Corydoras✅ CompatiblePeaceful · 3.2 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–24 °C — no size, zone or temperament conflicts.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Red Phantom Tetra✅ CompatiblePeaceful · 4 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 Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Tailspotted Oto✅ CompatiblePeaceful · 3.5 cm · Medium 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.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Keep Tailspotted Oto in a shoal of 6+ 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight 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 clearly outsizes Northern Glowlight Danio and is semi-aggressive; risky unless the tank is big and well-planted.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Northern Glowlight 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.
- 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight Danio 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.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Desert Goby clearly outsizes Northern Glowlight Danio and is semi-aggressive; risky unless the tank is big and well-planted.
- Keep Northern Glowlight Danio 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 Northern Glowlight Danio 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.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta is semi-aggressive and may chase or nip the smaller Northern Glowlight Danio — plant heavily and break up sight lines.
- Northern Glowlight Danio is small enough to tempt Eastern Betta; only risk it in a densely planted setup with hiding spots.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra is semi-aggressive and may chase or nip the smaller Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight Danio 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.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Humpbacked Tetra and Northern Glowlight Danio are close in size, but the semi-aggressive one tends to dominate — add northern glowlight danio in a group to spread the pressure.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Northern Glowlight Danio 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 Northern Glowlight 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.
- 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight 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.
- 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight 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)
- Expect Silvertip Tetra to harass Northern Glowlight Danio at times; give dense cover and watch them at feeding.
- Keep Northern Glowlight 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.
- 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight Danio 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 Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight Danio 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)
- Expect Tiger Badis to harass Northern Glowlight Danio at times; give dense cover and watch them at feeding.
- Keep Northern Glowlight Danio 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 is aggressive and may chase or nip the smaller Northern Glowlight Danio — plant heavily and break up sight lines.
- Keep Northern Glowlight Danio 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 3.5 cm): Alligator Gar will treat Northern Glowlight Danio as food.
- Alligator Gar is aggressive and may chase or nip the smaller Northern Glowlight 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 Northern Glowlight 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)
- Clown Knifefish (90 cm) is big enough to swallow the 3.5 cm Northern Glowlight Danio whole.
- Expect Clown Knifefish to harass Northern Glowlight Danio at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Northern Glowlight 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)
- Fire Eel (100 cm) is big enough to swallow the 3.5 cm Northern Glowlight Danio whole.
- Fire Eel clearly outsizes Northern Glowlight Danio 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 Northern Glowlight 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)
- Koi (90 cm) is big enough to swallow the 3.5 cm Northern Glowlight Danio whole.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Northern Glowlight 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)
- Size gap is too large (120 vs 3.5 cm): Redtail Catfish will treat Northern Glowlight Danio as food.
- Expect Redtail Catfish to harass Northern Glowlight Danio 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 Northern Glowlight 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 3.5 cm): Spotted Gar will treat Northern Glowlight Danio as food.
- Spotted Gar is aggressive and may chase or nip the smaller Northern Glowlight 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 Northern Glowlight 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)
- Northern Glowlight Danio is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Wels Catfish clearly outsizes Northern Glowlight Danio 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 Northern Glowlight 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)
- Northern Glowlight Danio is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
- Expect Wolf Cichlid to harass Northern Glowlight 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 Northern Glowlight 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.
Northern Glowlight Danio care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 3.5 cm (1.4 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 18–24 °C (64–75 °F)
- pH
- 6.5–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 2–4 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Cyprinidae
- Origin
- Northern Myanmar — upper Mali Hka River drainage, Putao region
What is a Northern Glowlight Danio?
The Northern Glowlight Danio (Danio flagrans, also traded as Celestichthys flagrans) is a small schooling cyprinid from the high-altitude streams of far northern Myanmar. Adults top out at roughly 3.5 cm (about 1.4 in) — firmly nano territory — yet they punch well above their weight in colour. A pale silver body carries vivid orange-red horizontal stripes that are criss-crossed by bold vertical dark bars, producing a latticed flame pattern unlike anything else in the danio family. It is this barred quality that separates D. flagrans from its close relative the Glowlight Danio (Celestichthys choprae), which has a cleaner, uninterrupted stripe.
This species remains genuinely scarce in the aquarium trade. Expect to source it through specialist retailers, hobbyist importers, or breeders rather than chain pet stores. The patience required to find a group is rewarded: a shoal of eight or more in a well-planted, cool-water tank is one of the most visually arresting sights in the nano fishkeeping hobby.
Where does the Northern Glowlight Danio come from?
Danio flagrans originates from the upper Mali Hka River drainage in the Putao region of Kachin State, northern Myanmar — one of the most remote and biologically rich corners of mainland Southeast Asia. This area sits at the foothills of the easternmost Himalayas, and the streams it calls home are fed by mountain snowmelt and monsoon runoff. The water is fast-moving, well-oxygenated, clear, and cool for most of the year. Substrates tend to be gravel and smooth stone rather than silt, with riparian vegetation providing dappled light and marginal plant growth along the banks.
Understanding this origin is the single most useful piece of care information for this species. Everything about successful husbandry — the temperature ceiling, the need for current, the soft-to-moderately-hard water — flows directly from where it was collected.
What size tank does the Northern Glowlight Danio need?
A minimum of 60 litres (about 16 US gallons) is recommended, and this is not the place to go smaller. The species needs a group of at least eight individuals to school naturally and to distribute any social tension, and that group requires both horizontal swimming room and enough water volume to stay stable. A footprint of roughly 60 × 30 cm or larger gives the shoal room to move together as a unit — one of the main behaviours you are buying them for.
Aquascape the tank to suit a montane stream: a dark or sandy substrate, smooth river pebbles, some driftwood branches, and a mix of fine-leaved plants (such as Cryptocoryne, java fern, or mosses) provide cover and visual interest. Floating plants or broad-leaved emergent plants are welcome, but leave open swimming lanes in the middle column, where this species spends most of its time. A tightly fitted lid is a sensible precaution — active danios are capable jumpers, especially when startled.
What water parameters does the Northern Glowlight Danio need?
- Temperature: 18–24 °C (64–75 °F). The everyday sweet spot is 20–22 °C; avoid sustained temperatures above 25 °C.
- pH: 6.5–7.5 — slightly acidic to neutral.
- Hardness: 2–12 dGH — soft to moderately hard.
- Current: moderate to brisk, with strong surface agitation to maintain dissolved oxygen.
In a temperate house with no heater, room temperature often sits comfortably within range for much of the year, which is one practical advantage of keeping this fish. If your room runs warm in summer, a small fan directed at the water surface or a purpose-built aquarium chiller may be needed. Never use a heater set above 24 °C. Filtration should be efficient; these fish come from pristine water, and ammonia or nitrite spikes are poorly tolerated. Target nitrates below 20 ppm through regular partial water changes of around 25–30% weekly.
What does the Northern Glowlight Danio eat?
Danio flagrans is an omnivore with a strong preference for small live or frozen invertebrates in the wild — insects, zooplankton, and small crustaceans form the bulk of its natural diet. In the aquarium, offer:
- Staple: a quality micro-pellet or fine-crushed flake that fits comfortably in a 3.5 cm mouth.
- Regular supplements: frozen or live daphnia, baby brine shrimp, cyclops, and micro-worms.
- Occasional treats: finely chopped bloodworm or white mosquito larvae.
Feed small amounts two to three times daily, giving only what the group consumes in two minutes. Because the fish are active and fast, target feeding is rarely necessary — they will find food throughout the water column. Variety is more important than volume; a diet of staple pellets alone will produce dull colour and suppressed immune function compared with a mixed regime.
How does the Northern Glowlight Danio behave, and what are compatible tank mates?
This is a peaceful, active schooling fish that presents no threat to tank mates of similar or larger size. It occupies the middle column and is perpetually in motion — the shoal wheels, splits, and reforms in a way that is genuinely mesmerising in a well-planted tank. Aggression within the group is limited to minor chasing that dissipates quickly when the group is large enough; eight is the workable minimum, ten or more is better.
Choose tank mates that share the same temperature requirements — this is the primary constraint, and it rules out most tropical community fish. Good companions include other cool-water, peaceful small fish: ember tetras are marginal on temperature (check your specific conditions); hillstream loaches (Beaufortia spp., Gastromyzon spp.) share the same fast-water preference and add bottom-level activity; smaller Devario species are natural ecological neighbours; and some corydoras species tolerate the lower end of their own range, making them workable at 20–22 °C. Avoid fin-nippers, boisterous cichlids, or anything large enough to treat a 3.5 cm danio as prey.
For a full list of tested pairings, see Northern Glowlight Danio tank mates.
How do you tell male and female Northern Glowlight Danios apart?
Sexing is straightforward in mature fish. Females are noticeably rounder in the belly, especially when gravid with eggs, and this body depth is visible even when viewed from above. Males are slimmer and more streamlined, and when in good condition — well-fed on varied diet and kept in optimal water — their orange-red stripes intensify noticeably compared with females. During spawning condition, males may also display more actively toward one another and toward females, with brief parallel swimming and fin-spreading.
In young fish below 2 cm the sexes are difficult to distinguish. Purchase a group of eight or more and the sexes will sort themselves out as the fish mature.
How do you breed the Northern Glowlight Danio?
Breeding D. flagrans is rated hard — not because the fish are unwilling, but because acquiring conditioned adults, replicating precise water conditions, and raising fry from such a small species all require experience and attention. That said, it has been accomplished by dedicated hobbyists, and doing so contributes meaningfully to an ex-situ population of a species with a restricted wild range.
Condition a group of males and females separately for two to three weeks on a diet heavy in live and frozen foods. Set up a dedicated breeding tank of 20–40 litres with a temperature of 20–22 °C, slightly soft water (4–6 dGH), pH around 7.0, and a dense clump of fine-leaved plants or a spawning mop. Spawning is an egg-scatter event: the pair (or group) releases small adhesive eggs among the plants or over the substrate. Adults will eat eggs given the chance, so either remove the adults after spawning or use a mesh or egg-crate barrier above the substrate. Eggs typically hatch in 48–72 hours at 20 °C; fry are very small and require infusoria or commercial fry foods for the first week before graduating to baby brine shrimp nauplii.
What diseases are common in the Northern Glowlight Danio?
Danio flagrans has no species-specific diseases, but it is susceptible to the standard ailments that affect any small cyprinid kept in suboptimal conditions:
- White spot (ich): The classic white-spot parasite (Ichthyophthirius multifiliis) is the most common problem in newly acquired fish. Warm-water treatments used for tropical fish may be insufficient at the lower temperatures this species prefers — use treatments rated for cooler water and follow package directions.
- Fin rot and bacterial infections: Usually a consequence of poor water quality or physical damage. Weekly water changes and avoiding sharp decor are the main preventative measures.
- Velvet (Oodinium): A fine golden-dust appearance on the body. Dimming lights and maintaining pristine water slow progression; treat with a copper-based product rated for small fish.
- Intestinal parasites: Can be introduced with live foods. Quarantine new fish for three to four weeks in a separate tank before introducing them to an established shoal.
Prevention is straightforward: clean, cool, well-oxygenated water; a varied diet; a proper quarantine protocol for new arrivals; and a group large enough that individual fish are not chronically stressed.
Health note: medication dosing and disease diagnosis are beyond the scope of a care profile. For sick fish, confirm symptoms against a reputable veterinary or fish-health source before treating.
How long does the Northern Glowlight Danio live?
A well-maintained Northern Glowlight Danio lives 2–4 years. As with most small cyprinids, the upper end of that range is achievable only with consistently good husbandry: stable cool temperatures, excellent water quality, a varied diet, and a large enough group to allow natural behaviour. Fish kept too warm, in poor water, or in undersized groups tend to sit at the shorter end of the lifespan range. Because the species is uncommon in the trade and may be wild-collected, fish purchased from importers could be of unknown age; sourcing from breeders gives better insight into a fish’s age and history.
Frequently asked questions
What is the difference between the Northern Glowlight Danio and the regular Glowlight Danio?
The regular Glowlight Danio is Celestichthys choprae, which has a smoother horizontal stripe pattern. The Northern Glowlight Danio (Danio flagrans) has more prominent vertical dark bars crossing the red stripes, giving it a bolder, barred appearance. It also comes from a different, more northerly part of Myanmar and prefers slightly cooler water.
Why does my Northern Glowlight Danio need cooler water than other danios?
It lives in high-altitude, fast-flowing montane streams in northern Myanmar where temperatures rarely exceed 24 °C. Keeping it too warm — above 25 °C for extended periods — stresses the fish and shortens its lifespan. Aim for 20–22 °C as the everyday target, with natural room-temperature fluctuation acceptable in a cool climate.
What you need to keep a northern glowlight danio
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 18–24 °C (64–75 °F), a gentle filter that won't batter a northern glowlight danio in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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