Photo: NasserHalaweh (CC BY-SA 4.0) — via Wikimedia Commons
Glowlight Rasbora (Trigonostigma hengeli)
A tiny, coppery schooling fish whose glowing orange stripe and neat black wedge light up any nano or planted tank.
Will it live with a Glowlight Rasbora?
We compare each fish against your glowlight rasbora 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glowlight Rasbora 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; 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 Glowlight Rasbora 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 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glowlight Rasbora 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)
- 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 Glowlight Rasbora 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, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Rasbora 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; 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 Glowlight Rasbora 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 23–26 °C — no size, zone or temperament conflicts.
- Keep Glowlight Rasbora 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)
- 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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Emperor Tetra✅ CompatiblePeaceful · 4 cm · Easy 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 Glowlight Rasbora 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; 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 Glowlight Rasbora 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 23–28 °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 Glowlight Rasbora 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, 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 Glowlight Rasbora 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)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Glowlight Rasbora 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 Tetra✅ CompatiblePeaceful · 4 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.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Rasbora 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 Glowlight Rasbora 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 Glowlight Rasbora 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)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glowlight Rasbora 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.
- Northern Glowlight Danio✅ CompatiblePeaceful · 3.5 cm · Medium care · 18–24 °C (64–75 °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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Northern Glowlight Danio in a shoal of 8+ 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 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glowlight Rasbora 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, 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 Glowlight Rasbora 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 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Rasbora 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glowlight Rasbora 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 Glowlight Rasbora 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, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
- Keep Glowlight Rasbora 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 Glowlight Rasbora — plant heavily and break up sight lines.
- Keep Glowlight 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 clearly outsizes Glowlight Rasbora 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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Expect Black Skirt Tetra to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Expect Desert Goby to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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 Glowlight 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.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Eastern Betta clearly outsizes Glowlight Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Glowlight Rasbora is small enough to tempt Eastern Betta; only risk it in a densely planted setup with hiding spots.
- Keep Glowlight Rasbora 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 clearly outsizes Glowlight Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
- Keep Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Humpbacked Tetra to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Glowlight 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 Glowlight 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.
- Rainbow Emperor Tetra⚠️ With cautionSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Expect Rainbow Emperor Tetra to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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)
- Serpae Tetra and Glowlight Rasbora are close in size, but the semi-aggressive one tends to dominate — add glowlight rasbora in a group to spread the pressure.
- Keep Glowlight 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 Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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)
- Expect Spotfin Betta to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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 Glowlight Rasbora — plant heavily and break up sight lines.
- Keep Glowlight 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 and Glowlight Rasbora are close in size, but the semi-aggressive one tends to dominate — add glowlight rasbora in a group to spread the pressure.
- Keep Glowlight 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)
- Expect Wine Red Betta to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Keep Glowlight 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 3.5 cm): Alligator Gar will treat Glowlight Rasbora as food.
- Expect Alligator Gar to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Glowlight 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)
- Clown Knifefish (90 cm) is big enough to swallow the 3.5 cm Glowlight Rasbora whole.
- Expect Clown Knifefish to harass Glowlight Rasbora 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 Glowlight 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)
- Fire Eel (100 cm) is big enough to swallow the 3.5 cm Glowlight Rasbora whole.
- Expect Fire Eel to harass Glowlight 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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Size gap is too large (90 vs 3.5 cm): Koi will treat Glowlight Rasbora as food.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Glowlight 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)
- Redtail Catfish (120 cm) is big enough to swallow the 3.5 cm Glowlight Rasbora whole.
- Expect Redtail Catfish to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Glowlight 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)
- Glowlight Rasbora is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Spotted Gar clearly outsizes Glowlight 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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Wels Catfish (300 cm) is big enough to swallow the 3.5 cm Glowlight Rasbora whole.
- Expect Wels Catfish to harass Glowlight Rasbora 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 Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Wolf Cichlid (72 cm) is big enough to swallow the 3.5 cm Glowlight Rasbora whole.
- Wolf Cichlid is aggressive and may chase or nip the smaller Glowlight Rasbora — plant heavily and break up sight lines.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Glowlight 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.
Glowlight Rasbora care specs
- Care level
- Easy
- Breeding
- Hard
- Max size
- 3.5 cm (1.4 in)
- Min tank size
- 40 L (10.6 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 5.5–7.5
- Hardness
- 1–10 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 8+ (shoaling)
- Family
- Danionidae
- Origin
- Southeast Asia — Sumatra and the Malay Peninsula (blackwater streams and peat swamps)
What is a Glowlight Rasbora?
The Glowlight Rasbora (Trigonostigma hengeli) is a diminutive schooling fish native to the blackwater streams and peat swamps of Sumatra and the Malay Peninsula. At a maximum of 3.5 cm (1.4 in), it is one of the smallest members of its genus and a standout choice for nano tanks and planted aquascapes.
Its defining feature is a vivid copper-orange lateral stripe ending in a neat dark “rocket” wedge at the rear — the marking is smaller and more pointed than the broad triangular blaze of the closely related Harlequin Rasbora (T. heteromorpha), making it a reliable field mark when the two species share a store shelf. In good light, the stripe shifts to warm gold that earns the fish its common name.
Like all Trigonostigma species, the Glowlight Rasbora is a committed shoaler. A group of eight or more moving in tight formation through a planted tank is one of the more rewarding sights in freshwater fishkeeping — and that group dynamic is also what keeps the fish confident and in full colour. Lone or under-numbered specimens become timid and pale.
Where does the Glowlight Rasbora come from?
Wild T. hengeli inhabit slow-moving blackwater streams, forest pools and peat swamps across the southern Malay Peninsula and Sumatra. These habitats share a common character: water stained amber by tannins from decaying leaf litter, very low mineral content, low pH and dense overhanging vegetation.
That origin matters in practice. Fish adapted to near-distilled, acidic water are genuinely stressed by the hard, alkaline tap water found in many cities — they survive, but colour dims, fin quality declines and lifespan shortens. Getting as close as possible to the native blackwater profile rewards effort with visibly better fish.
What size tank does a Glowlight Rasbora need?
The minimum is 40 L (10 gal), assuming a school of eight — the smallest group that produces natural shoaling behaviour. In practice a 60–75 L (16–20 gal) tank gives more stable water chemistry, more swimming room and better scope for planting.
Footprint matters more than depth. Glowlight Rasboras are active mid-water swimmers that appreciate horizontal space; a longer, shallower tank suits them better than a tall column. A tight-fitting lid is advisable — small rasboras jump when startled.
For decor, lean into the blackwater aesthetic: dark fine substrate, driftwood, scattered Indian almond leaves, and floating or stem plants to diffuse light. Clear-water planted scapes also work, but the fish look most spectacular against a darker backdrop.
What water parameters do Glowlight Rasboras need?
- Temperature: 23–28 °C (73–82 °F). A reliable heater is essential; this is a tropical species from consistently warm equatorial habitats.
- pH: 5.5–7.5. The fish can adapt to neutral tap water when acclimated carefully, but 6.0–6.8 brings out the best colour and is closer to the native range.
- Hardness: 1–10 dGH. Soft water is the single most important parameter to get right. Hardness above 10–12 dGH will dull the fish noticeably over time.
- Ammonia / Nitrite: Zero. The tank must be fully cycled before fish are introduced.
- Nitrate: Below 20 ppm with regular water changes.
If your tap water is hard, cut it with reverse-osmosis water or use a peat filter insert to soften and acidify. Adding Indian almond leaves provides tannins and mild antibacterial benefit; the amber tint is entirely appropriate for this species.
What do Glowlight Rasboras eat?
Glowlight Rasboras are omnivores and unfussy feeders. A good-quality micro-pellet or finely crushed flake forms the nutritional base — standard-size flake often goes uneaten and pollutes the water, so always crumble it fine. Supplement the staple two or three times a week with small live or frozen foods: daphnia, baby brine shrimp, micro-worms or cyclops. These also act as a conditioning trigger if breeding is the goal.
Feed small amounts once or twice daily — only what is consumed within two to three minutes. Overfeeding degrades water quality quickly in the smaller tanks these fish typically occupy.
Are Glowlight Rasboras peaceful — and what fish can live with them?
The Glowlight Rasbora is entirely peaceful and poses no threat to tank mates. It is, however, small and somewhat delicate — it can be outcompeted at feeding time or stressed by boisterous or large species. The best companions are other small, peaceful community fish that share similar soft, warm water requirements.
Good choices include other small rasboras (Chili, Lambchop), nano tetras (Ember, Green Neon), small Corydoras, Otocinclus and peaceful dwarf gouramis. Neocaridina and Caridina shrimp and Nerite snails are generally safe, though very small shrimp fry may occasionally be picked at. Avoid cichlids, large barbs, aggressive gouramis, Tiger Barbs and anything large enough to view a 3.5 cm fish as a meal.
For a full list of tested pairings, see Glowlight Rasbora tank mates.
How do you tell male from female Glowlight Rasboras?
Sexual dimorphism in T. hengeli is subtle but consistent. Males are slimmer and carry a more vivid, saturated copper-orange stripe. Females are slightly deeper-bodied, a difference that becomes more pronounced when they are gravid — a ripe female appears distinctly rounder when viewed from above.
Accurate sexing is easiest in a group of eight or more, where individuals can be compared side by side. Juveniles are essentially impossible to sex with confidence; wait until the fish approach adult size before attempting to distinguish males from females.
How do Glowlight Rasboras breed?
Breeding T. hengeli in captivity is achievable but rated hard. The fish rarely spawn spontaneously in a community tank. Condition a small group of adults (two or three pairs) in a dedicated, heavily planted breeding tank of around 20–30 L (5–8 gal) with very soft, acidic water (pH 6.0–6.5, hardness under 4 dGH) at the warmer end of their range, around 26–28 °C (79–82 °F).
Like other Trigonostigma species, Glowlight Rasboras scatter adhesive eggs on the undersides of broad leaves — Java fern and Anubias are traditional choices. Adults will eat eggs and fry, so remove parents after spawning or use a mesh-bottomed box. Eggs hatch within 24–36 hours; fry are tiny and need infusoria or commercial fry foods before graduating to baby brine shrimp and micro-worms. Raising fry successfully demands pristine water and patience — this is a species for aquarists who enjoy the challenge.
What diseases commonly affect Glowlight Rasboras?
Most health problems are preventable with good husbandry:
- White Spot (Ich): Classic white-spot parasite triggered by temperature swings or unquarantined fish. Prevent with a stable heater and a quarantine period for all new arrivals.
- Velvet (Oodinium): A dusty gold sheen on the flanks, often missed in low light. Common in newly imported or stressed fish; quarantine and stable water are the best prevention.
- Fin Rot: Fraying fins, almost always caused by poor water quality or chronic stress. Fix the water first.
- Neon Tetra Disease: Rare but incurable; presents as loss of colour in the stripe. Buy from reputable sources and quarantine all new fish.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. If a fish appears sick, cross-reference symptoms against a reputable veterinary or fish-health source before treating — misdiagnosis and over-medication can cause more harm than the original condition.
How long do Glowlight Rasboras live?
A well-kept Glowlight Rasbora lives 3–5 years. That range is achievable with consistent soft warm water, a varied diet, a stable tank and a school of eight or more. Fish kept in hard water, undersized groups or poorly maintained tanks rarely approach the upper end.
Get the water chemistry right, keep the group large, and a school of Glowlight Rasboras will reward you with years of easy, lively community fishkeeping.
Frequently asked questions
How is the Glowlight Rasbora different from the Harlequin Rasbora?
Trigonostigma hengeli is noticeably smaller (3.5 cm vs 4.5 cm) and its black marking is a small rear wedge rather than the large triangular patch of the harlequin (T. heteromorpha). The orange stripe is also more vivid copper-gold in hengeli. All three Trigonostigma species prefer soft, acidic water, but hengeli is the most delicate of the trio.
What water parameters does the Glowlight Rasbora need?
It is a blackwater fish that thrives in soft, slightly acidic water: pH 5.5–7.5 and hardness 1–10 dGH. It tolerates neutral tap water if conditioned gradually, but really shows its best colour and schooling behaviour in peat-filtered or RO-supplemented soft water. Hard, alkaline tap water shortens lifespan.
What you need to keep a glowlight 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 glowlight rasbora in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
As an Amazon Associate we earn from qualifying purchases — buying through these links costs you nothing extra.
