Tetras · Hemigrammus erythrozonus

Glowlight tetra care guide

Also called: Glow light tetra, Glowlight characin

The glowlight tetra is a small, peaceful tetra with a glowing orange-red stripe along its side. It is a hardy beginner fish for planted community tanks. Keep at least 6 in warm, soft to medium-hard water.

Glowlight tetras need a tank of at least 15 gallons (57 L), a group of 6 or more, and water at 24–28°C (75–82°F) with a pH of 5.5–7.5. They grow to about 4 cm (1.6 in) and are peaceful.

Plan a tank with glowlight tetrasSee all tank mates

Glowlight tetra quick facts

Scientific nameHemigrammus erythrozonus
FamilyAcestrorhamphidae
OriginEssequibo River, Guyana (most are farm-bred)
Adult size4 cm (1.6 in)
Minimum tank15 gallons (57 L), at least 60 cm (24 in) long
Temperature24–28°C (75–82°F)
pH5.5–7.5
Hardness (GH)2–12 dGH
Group size6 or more (schooling fish)
TemperamentPeaceful
Swims atMiddle
DietOmnivore
Care levelEasy
Lifespan3–5 years
Safe with shrimp?Mostly (eats baby shrimp)
Safe with plants?Yes

Tank setup

A group of 6 fits in a 15-gallon (57 L) tank about 24 in (60 cm) long, but 20 gallons (76 L) lets you keep a larger, more natural group. Plants, driftwood and a dark substrate help them feel safe and bring out their glow. Floating plants that dim the light help too.

How many glowlight tetras in a tank?

The smallest common tank that suits glowlight tetras is a 15 gallon. Here is roughly how many fit in each size when they are the only fish, based on adult size and waste output. Leave room if you want tank mates.

TankGlowlight tetras (alone)
3 gallonToo small
5 gallonToo small
10 gallonToo small
15 gallon6–20
20 gallon6–27
20 gallon long6–27
29 gallon6–39
40 gallon6–54
55 gallon6–74
75 gallon6–102
125 gallon6–170

What you need for glowlight tetras

Sized for a 15 gallon tank, the smallest common size that suits a group of 6 glowlight tetras. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.

Tank and equipment

Food and extras for glowlight tetras

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Water parameters

Keep the water warm at 75–82°F (24–28°C) with a pH of 5.5–7.5. They color up best in soft, slightly acidic water, but farm-bred fish cope with moderate hardness. They don't handle ammonia or nitrite well, so add them only to a fully cycled tank.

Best tank mates for glowlight tetras

These popular species share glowlight tetras' water needs and temperament. See the full list of 84 good matches.

Avoid keeping glowlight tetras with

  • Angelfish: Angelfish can eat glowlight tetras: they're small enough to fit in its mouth once it's grown.
  • Common goldfish: They need different temperatures: Glowlight tetra 24–28°C (75–82°F), common goldfish 15–22°C (59–72°F).
  • Fancy goldfish: They need different temperatures: Glowlight tetra 24–28°C (75–82°F), fancy goldfish 18–23°C (64–73°F).
  • Oscar: Oscar can eat glowlight tetras: they're small enough to fit in its mouth once it's grown.
  • Bala shark: Bala shark can eat glowlight tetras: they're small enough to fit in its mouth once it's grown.
  • Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful glowlight tetras.

Feeding

Glowlights eat almost any small food. Use a quality micro pellet or crushed flake as the staple. Add frozen or live daphnia, brine shrimp and bloodworms a few times a week for color and condition.

Behavior

They are calm, peaceful fish that shoal in the middle of the tank. Good tank mates include other small tetras, rasboras, corydoras, small livebearers, peaceful gouramis and dwarf cichlids. Avoid angelfish and any other fish big enough to swallow them.

Breeding

Glowlights are one of the easier tetras to spawn. Use a dim breeding tank with soft, acidic water around 80–84°F (27–29°C), fine-leaved plants or a spawning mop, and a gentle sponge filter. Remove the adults once eggs appear. The eggs hatch in about a day, and the fry need infusoria first, then baby brine shrimp.

Tips from experienced keepers

  • Add them to a mature, cycled tank. They are sensitive to ammonia and nitrite.
  • A dark substrate and a few floating plants make their orange stripe stand out.
  • Keep 8–10 if you have space. Bigger groups are bolder and spend more time in the open.
  • Don't keep them with angelfish or other fish big enough to eat a 1.5 in (4 cm) tetra.
  • Quarantine new fish for a few weeks before adding them to an established tank.

Frequently asked questions

How many glowlight tetras should be kept together?

Keep at least 6, and 8–10 is better. In bigger groups they are less shy and show better color.

Can glowlight tetras live with neon tetras?

Yes, if you keep the tank around 24–25 °C (75–77 °F), where their ranges overlap. Glowlights like warmer water than neons, so do not run it hotter. Keep each species in its own group of 6 or more.

Will glowlight tetras eat shrimp?

They rarely bother adult dwarf shrimp, but they will eat tiny shrimplets. Dense moss and plants let enough babies survive for the colony to grow.

Sources

We checked these references when writing this page. Values are for healthy long-term keeping, not survival limits. Last reviewed 2026-10-13. See our editorial policy.