Photo: Strolgen (Public domain) — via Wikimedia Commons
Glowlight Tetra (Hemigrammus erythrozonus)
A neon-bright orange stripe that seems to glow under aquarium lighting — this peaceful nano tetra is one of the easiest schooling fish you can keep.
Will it live with a Glowlight Tetra?
We compare each fish against your glowlight tetra 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)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Amapá Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 24–27 °C (75–81 °F)
- Compatible on the things that matter: shared water near 24–27 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Phantom Tetra✅ CompatiblePeaceful · 4.5 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Phantom Tetra 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, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ 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 Glowlight Tetra in a shoal of 6+ 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 23–27 °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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Cardinal Tetra in a shoal of 6+ 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 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Flame Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
- Gold Tetra✅ CompatiblePeaceful · 4.5 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold 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 Tetra in a shoal of 6+ 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, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ 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 Tetra in a shoal of 6+ 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)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Glowlight Tetra in a shoal of 6+ 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 Tetra in a shoal of 6+ 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)
- 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Purple Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rainbow Emperor Tetra✅ CompatibleSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Rainbow Emperor Tetra 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
- Rosy Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Rosy Tetra in a shoal of 6+ or it gets stressed and nippy.
- Rummy Nose Rasbora✅ 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Rummy Nose Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Sparkling Gourami✅ CompatiblePeaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Strawberry Betta✅ CompatiblePeaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 22–27 °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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Threadfin Rainbowfish✅ CompatiblePeaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Threadfin Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Otocinclus✅ CompatiblePeaceful · 4 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 Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Otocinclus in a shoal of 6+ or it gets stressed and nippy.
- Yellow Phantom Tetra✅ CompatiblePeaceful · 4 cm · Easy care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Yellow Phantom Tetra 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 and Glowlight Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Keep Glowlight Tetra in a shoal of 6+ 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 and Glowlight Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Glowlight Tetra in a shoal of 6+ 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 and Glowlight Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cherry Shrimp⚠️ With cautionPeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Glowlight Tetra may eat Cherry Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Desert Goby and Glowlight Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Keep Glowlight Tetra in a shoal of 6+ 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Ghost Shrimp⚠️ With cautionPeaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
- Glowlight Tetra may eat Ghost Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Ghost Shrimp 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 Tetra 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 Tetra in a shoal of 6+ 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 Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ 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 Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Keep Glowlight Tetra in a shoal of 6+ 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 Tetra at times; give dense cover and watch them at feeding.
- Keep Glowlight Tetra in a shoal of 6+ 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 and Glowlight Tetra are close in size, but the semi-aggressive one tends to dominate — add glowlight tetra in a group to spread the pressure.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Striped Red-Eye Puffer to harass Glowlight Tetra at times; give dense cover and watch them at feeding.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Expect Tiger Badis to harass Glowlight Tetra at times; give dense cover and watch them at feeding.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Tiger Shrimp⚠️ With cautionPeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Glowlight Tetra may eat Tiger Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ 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 Glowlight Tetra — plant heavily and break up sight lines.
- Keep Glowlight Tetra in a shoal of 6+ 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 4 cm Glowlight Tetra whole.
- Expect Alligator Gar to harass Glowlight Tetra 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 Tetra in a shoal of 6+ 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 4 cm Glowlight Tetra whole.
- Clown Knifefish clearly outsizes Glowlight Tetra 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 Glowlight Tetra in a shoal of 6+ 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 4 cm): Fire Eel will treat Glowlight Tetra as food.
- Fire Eel is semi-aggressive and may chase or nip the smaller Glowlight Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Glowlight Tetra in a shoal of 6+ 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 4 cm Glowlight Tetra whole.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Glowlight Tetra is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
- Redtail Catfish clearly outsizes Glowlight Tetra 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 Glowlight Tetra in a shoal of 6+ 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 4 cm): Spotted Gar will treat Glowlight Tetra as food.
- Expect Spotted Gar to harass Glowlight Tetra at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Glowlight Tetra in a shoal of 6+ 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 4 cm Glowlight Tetra whole.
- Wels Catfish is aggressive and may chase or nip the smaller Glowlight Tetra — plant heavily and break up sight lines.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Glowlight Tetra in a shoal of 6+ 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 4 cm Glowlight Tetra whole.
- Wolf Cichlid is aggressive and may chase or nip the smaller Glowlight Tetra — 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 Tetra in a shoal of 6+ 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 Tetra care specs
- Care level
- Easy
- Breeding
- Hard
- Max size
- 4 cm (1.6 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 5.8–7.5
- Hardness
- 1–12 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 6+ (shoaling)
- Family
- Characidae
- Origin
- South America — Essequibo River basin, Guyana
What is a Glowlight Tetra?
The glowlight tetra (Hemigrammus erythrozonus) is a small freshwater characid from South America whose defining feature is immediately obvious: a vivid iridescent stripe — copper-orange near the head, intensifying to a red-orange blaze at the base of the tail — that appears to genuinely glow under aquarium lighting. The body itself is translucent silver, which makes that stripe dramatic against a dark substrate or planted background.
At a maximum of 4 cm (1.6 in), it fits peaceful planted communities, soft-water biotopes, and beginner set-ups alike. Care is genuinely easy once stable water and appropriate company are in place — which is why the glowlight tetra has been a hobby staple for decades.
Where do Glowlight Tetras come from?
Glowlight tetras are native to the Essequibo River basin in Guyana, South America. The Essequibo and its tributaries drain ancient Guiana Shield forest, producing water that is naturally very soft, acidic, and tea-coloured from decomposing leaf litter and tannins — conditions that shaped every aspect of the fish’s care needs. Temperatures sit comfortably within the aquarium preference of 22–28 °C (72–82 °F).
Most commercially available fish are farm-raised in slightly harder water, giving them useful adaptability. Wild-caught specimens need careful, gradual acclimatisation.
What size tank does a Glowlight Tetra need?
The minimum is 60 litres (16 gal), enough for a school of six to eight fish with a few compatible bottom-dwellers. Longer tanks are preferred over tall ones — glowlight tetras swim actively in the middle of the water column and appreciate horizontal space.
A planted layout suits them well: dense planting at the back and sides, an open swimming area in the centre, and a dark fine-grain substrate. Some floating plants to diffuse overhead light, plus driftwood or dried leaf litter (Indian almond leaves work well), will encourage bold behaviour and intensify the stripe’s colour. Filtration should produce gentle to moderate current — strong flow tires them. A sponge filter or spray-bar-diffused hang-on-back is ideal.
What water parameters do Glowlight Tetras need?
- Temperature: 22–28 °C (72–82 °F) — mid-range around 24–26 °C suits most situations.
- pH: 5.8–7.5; they thrive best between 6.0 and 7.2 for everyday keeping.
- Hardness: 1–12 dGH; soft water is preferred, but moderately hard tap water is usually tolerated.
Stability matters more than chasing perfect numbers. Always cycle the tank fully before adding fish, keep up with weekly partial water changes (25–30%), and watch that nitrates do not creep up. Glowlight tetras are more sensitive to sudden swings than to water that sits slightly outside the ideal range. For breeding, tighter parameter control is needed — see the Breeding section below.
What do Glowlight Tetras eat?
Glowlight tetras are omnivores with small mouths, so food size matters as much as food type. In the wild they consume tiny invertebrates, zooplankton, insect larvae, and plant matter. In the aquarium a varied diet produces the best colour and condition:
- Staple: High-quality micro-pellets or fine-grade tropical flake, fed daily.
- Enrichment: Frozen or live daphnia, baby brine shrimp, and micro-worms several times a week.
- Occasional: Finely chopped bloodworm (frozen); small portions only, as bloodworm is rich and should not dominate the diet.
Feed small amounts once or twice a day — only what the fish consume in two to three minutes. Overfeeding fouls the water quickly in a planted nano tank. Because they are mid-water feeders, foods that sink slowly or are suspended briefly work best; dense pellets that sink rapidly to the bottom may be wasted.
Are Glowlight Tetras aggressive — and what fish can live with them?
Glowlight tetras are peaceful in all respects. They pose no threat to tankmates, do not nip fins, and cause no disruptions within a community. The only “conflict” worth mentioning is internal to the school: like most tetras, they establish a loose social hierarchy and may briefly chase each other, but this is harmless and decreases as group size increases. Keeping a minimum of six fish — ideally eight to ten — is the single most important step for a settled, confident school.
Compatible tankmates include other small, peaceful soft-water species: pygmy or panda corydoras, small rasboras (harlequin, lambchops), ember tetras, and similarly sized characids. Freshwater shrimp (neocaridina and caridina) are generally safe with glowlight tetras, which are small enough not to threaten adult shrimp, though shrimplets may occasionally be eaten. Dwarf gouramis can work in larger tanks. Avoid tiger barbs and other known fin-nippers, and avoid any fish large enough to swallow a 4 cm tetra whole.
For a full filterable list of what pairs well with this species, see Glowlight Tetra tank mates.
How do you tell male and female Glowlight Tetras apart?
Sexual dimorphism is subtle but visible on adult fish. Females are noticeably deeper-bodied, especially in the belly, and appear rounder when viewed from above — even more so when gravid (carrying eggs). Males are slimmer and more streamlined. Colour and stripe brightness are broadly similar in both sexes, so body profile is the most reliable indicator. Juveniles are difficult to sex; the difference in body depth only becomes reliable as fish approach adult size.
How do Glowlight Tetras breed?
Breeding glowlight tetras is rated hard — not because the fish are fragile, but because triggering and raising a spawn requires deliberate preparation. A dedicated breeding tank of 20–40 L (5–10 gal) works best: bare-bottomed with a mesh or grid so eggs fall out of reach of the parents (who will eat them), plus some Java moss or spawning mops as egg-deposit sites.
Water must be soft and acidic: target pH 6.0–6.5 and hardness below 4 dGH, ideally using RO or rainwater. Raise temperature slightly to 26–28 °C (79–82 °F). Condition the pair for one to two weeks on live or frozen daphnia and baby brine shrimp before introducing them together.
Eggs hatch in roughly 24–36 hours. Remove the parents immediately. Fry are tiny and need infusoria or commercial fry foods for the first week before moving on to baby brine shrimp. Variable success rates are normal even for experienced breeders; water-quality precision is the main lever.
What are common Glowlight Tetra diseases?
Glowlight tetras are reasonably robust when water quality is maintained, but share the usual small-tetra vulnerabilities:
- White spot (ich): Fine white granules on body and fins, typically triggered by a sudden temperature drop. Raise temperature gradually; treat as directed by a reputable fish-health source.
- Velvet (Oodinium): A fine gold or rust-coloured dusting, easiest to see under a torch. Usually introduced by new fish or live food — strict quarantine is the best prevention.
- Neon tetra disease: Glowlight tetras can contract it despite the name. Signs include fading colour, body cysts, and restlessness. There is no known cure; prevention through quarantine is essential.
- Fin rot: Almost always a water-quality problem. Consistent maintenance prevents it.
The common thread is prevention: a cycled, well-maintained tank and a two-to-four-week quarantine for all new arrivals.
Health note: symptoms of common diseases can overlap, and misdiagnosis leads to unnecessary stress and ineffective treatment. Confirm what you are seeing against a reputable veterinary or fish-health resource before reaching for any treatment.
How long do Glowlight Tetras live?
A well-kept glowlight tetra lives 3–5 years. The lower end is typical when water conditions fluctuate or the fish are kept in groups too small to reduce stress. Stable soft water, a varied diet, and a proper school of six or more regularly push fish toward the four-to-five-year mark.
Farm-raised fish are generally sold as juveniles, so unlike some species that arrive as young adults with the clock already ticking, you usually get the full lifespan ahead of you at purchase. A school at peak condition in a planted soft-water tank is among the most rewarding sights the freshwater hobby offers.
Frequently asked questions
How many glowlight tetras should I keep together?
Keep at least six, and ideally eight to ten. A small group of three or four will be shy, hide constantly, and show washed-out colours. A proper school of six or more becomes bold, stays out in the open, and the stripe looks dramatically brighter as fish mirror each other's movement.
Do glowlight tetras need soft, acidic water?
They prefer it. Wild fish come from the soft, tea-coloured rivers of Guyana, so they thrive between pH 6.0 and 7.0 with low hardness. They tolerate slightly harder neutral tap water well enough for everyday keeping, but breeding almost always requires soft, acidic conditioning around pH 6.0 and very low dGH.
What you need to keep a glowlight tetra
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a glowlight tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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