Glowlight Tetra

Hemigrammus erythrozonus

Also known as: Glowlight

Water Parameters

• Temperature: 22–28°C
• pH: 5.5–7.5
• Hardness (GH): 36–179 ppm (2–10 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

One of the gentlest and most reliable small community tetras, the glowlight is named for the single neon-bright copper-red stripe that appears lit from within against its near-transparent body. Hardier and more forgiving of water conditions than the neon, and far less fussy than the green neon, it is a genuine beginner fish that nonetheless rewards good keeping: in a mature planted tank, in a school of ten or more under low light, the understated glow becomes quietly spectacular. Peaceful to a fault, it can be bullied or outcompeted by boisterous tankmates, so it does best in a calm community. An easy, inexpensive, and underrated choice for a peaceful nano or small community tank.

Tankmates

A peaceful, gentle schooling tetra that must be kept in a group of at least six, ideally more, to feel secure and display the glowing orange-red line that runs the length of its translucent body. Too peaceful to bother anyone and small enough to be eaten by larger fish, so it belongs in a calm community of similarly-sized, non-aggressive species: other small tetras, rasboras, corydoras, and peaceful gouramis. Keep it away from fin-nippers (tiger barbs, serpae tetras) and from anything large enough to view it as food. Adult cherry shrimp are generally safe, though shrimplets may be eaten. A planted tank with subdued lighting and a darker substrate intensifies the glow.

Compatible with

• Ember Tetra
• Neon Tetra
• Harlequin Rasbora
• Bronze Corydoras
• Pygmy Corydoras
• Otocinclus
• Cherry Shrimp
• Honey Gourami

Avoid keeping with

• Betta
• Angelfish
• Large Cichlids
• Fin Nippers
• Tiger Barb

Common Problems

• pale colour and timidity in small groups
• stress from boisterous or nippy tankmates
• ich
• washed-out colour in bright, bare tanks

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20