Glowlight Tetra

Hemigrammus erythrozonus

Also sold as Glowlight · Glowlights

Synonyms Hemigrammus gracilis

Glowlight Tetra (Hemigrammus erythrozonus) is a peaceful freshwater fish that reaches about 4 cm (1.6 in) and swims in open water in a shoal. It wants 72–82°F (22–28°C) and pH 5.5–7.5, is kept in groups of 6 or more, and needs a tank of at least 60 L (16 gal).

Glowlight Tetra (Hemigrammus erythrozonus)

At a glance

TypeFish
Adult size4 cm (1.6 in)
Minimum tank60 L (16 gal)
Group size6 or more
Temperature72–82°F (22–28°C)
pH5.5–7.5
TemperamentPeaceful
GH2–15
Lifespan2–4 years

Before it goes in

  • Glowlight Tetra needs at least 60 L (16 gal). The smallest size in this library that clears that is the Dennerle Nano Cube 60L.
  • Keep 6 or more. Below that it hides, colours down and is far more likely to be picked on.
  • It is the wrong size to share a tank with Goldfish, Angelfish and Axolotl: it ends up as food.
  • It holds at 72–82°F (22–28°C). That shares a window with Betta and Cherry Shrimp.
  • A group of 6 takes up roughly 44% of what a Dennerle Nano Cube 60L will comfortably hold, so plan the rest of the stock around it.

What tank size does it need?

At least 60 L (16 gal). The smallest size here that clears it is the Dennerle Nano Cube 60L.

How many should I keep?

6 or more. Fewer than that and it spends its time hiding instead of out in the open.

What water does it want?

72–82°F (22–28°C), pH 5.5–7.5, GH 2–15.

How long does it live?

2–4 years in a tank that suits it. That is how long you are signing up for.

Good tank mates

Often compared with

Glowlight TetraHead and Tail Light TetraRummy Nose Tetra
Adult size4 cm4.5 cm5 cm
Min tank60 L68 L75 L
Group6+6+8+
Temperature72–82°F (22–28°C)75–82°F (24–28°C)75–84°F (24–29°C)

More livestock

Plan a tank with Glowlight Tetra →

Sources (4) · checked Sep 2026