Glowlight Tetra — Tank Size, Adult Size, Lifespan & Full Care Guide
Hemigrammus erythrozonus
Care requirements at a glance
| Scientific name | Hemigrammus erythrozonus |
|---|---|
| Group | Tetra |
| Adult size | 1.5 in (3.8 cm) |
| Minimum tank | 10 gallons |
| Temperature | 74-82°F |
| pH | 5.5-7.5 |
| Hardness | 2-15 dGH |
| Temperament | Peaceful |
| Social | Schooling (keep 6+) |
| Diet | Omnivore |
| Swim level | Mid |
| Care level | Easy |
| Lifespan | ~4 years |
How big do Glowlight Tetra get? Adult size explained
Adult glowlight tetra reach 1.5 inches (3.8 cm). Fish you buy are almost always juveniles at roughly 0.8″, so plan the tank around the adult number, never the size in the bag.
| Stage | Typical length |
|---|---|
| Size sold in stores | about 0.8″ |
| Half-grown | 1.1″ at roughly 4 months |
| Full adult size | 1.5″ (3.8 cm) by 8 months |
Glowlight Tetra tank size: minimum vs recommended
The 10-gallon figure is a floor, not a target. It assumes a cycled, filtered tank and an owner who does weekly water changes. Glowlight Tetra need at least 6 individuals, so the real question is not "will one fit" but "will 6 of them fit".
Numbers assume glowlight tetra are the main occupants with light additional stocking. Use the stocking calculator to model a mixed community.
Glowlight Tetra group size
Glowlight Tetra are a shoaling species. In groups below 6 they show measurable stress behaviour: faded colour, hiding and skittishness. Minimum: 6. Better: 8–12. If your budget forces a choice between more species and bigger groups, always choose bigger groups.
Glowlight Tetra water parameters
| Parameter | Range | Notes |
|---|---|---|
| Temperature | 74–82°F | keep it stable; an adjustable heater is essential — temperature swings cause more disease than a slightly wrong average. |
| pH | 5.5–7.5 | stability beats the exact number |
| Hardness (GH) | 2–15 dGH | |
| Ammonia (NH₃) | 0 ppm | any reading means the tank is not cycled |
| Nitrite (NO₂) | 0 ppm | any reading is an emergency — water change now |
| Nitrate (NO₃) | under 20–40 ppm | controlled by water changes and live plants |
What do Glowlight Tetra eat? Diet and feeding
Micropredator omnivores. Crushed quality flake, micro pellets, and frozen daphnia or baby brine shrimp. Small mouths — keep food fine.
The single most common feeding error is quantity, not quality. Feed what disappears in about two minutes, once or twice a day, and the tank stays clean.
How long do Glowlight Tetra live?
Glowlight Tetra tank mates: what works and what does not
Compatibility is decided by four things, in this order: water parameters (74–82°F, pH 5.5–7.5), adult size, temperament, and swimming level.
Good tank mates
Avoid these
Check any pairing in the compatibility tool →
Breeding Glowlight Tetra
Egg-scatterers needing soft, dim water to spawn. Eggs and fry are light-sensitive; breeding tanks are kept nearly dark for the first days.
Male vs female glowlight tetra
Females are noticeably deeper-bodied and rounder; males stay slim. The stripe is identical in both sexes.
Glowlight Tetra health, diseases and prevention
Prevention beats treatment every time: quarantine new arrivals for two weeks, keep the tank understocked rather than at maximum capacity, and do a consistent weekly water change.
What does a glowlight tetra setup cost?
| Item | Typical cost |
|---|---|
| Aquarium, 10 gal | $40 |
| Filter | $22 |
| Heater | $16 |
| Light | $22 |
| Substrate & decor | $25 |
| Liquid test kit | $32 |
| 6× glowlight tetra | $18 |
| Estimated total | $175 |
Indicative US retail prices for a new setup.
Glowlight Tetra FAQ
What size tank do glowlight tetra need?
The minimum tank size for glowlight tetra is 10 gallons. Because they need a group of at least 6, we recommend 20 gallons or larger for a healthy long-term setup.
How big do glowlight tetra get?
Adult glowlight tetra reach 1.5 inches (3.8 cm). Store specimens are usually juveniles at around 0.8 inches, so always plan the tank around the adult size.
How long do glowlight tetra live?
Glowlight Tetra typically live about 4 years in a well-maintained aquarium. Stable water quality and a varied diet are the two biggest factors in reaching the upper end of that range.
How many glowlight tetra should I keep together?
Keep at least 6 together. Groups of 8 to 12 show noticeably better colour and more natural behaviour. Below 6 they become stressed, hide and lose colour.
What water parameters do glowlight tetra need?
Keep glowlight tetra at 74–82°F, pH 5.5–7.5, and hardness 2–15 dGH. Ammonia and nitrite must both read zero at all times.
Are glowlight tetra good for beginners?
Glowlight Tetra are rated easy. They are a solid choice for a first community tank as long as the tank is cycled first.
What do glowlight tetra eat?
Micropredator omnivores. Crushed quality flake, micro pellets, and frozen daphnia or baby brine shrimp. Small mouths — keep food fine.
Do glowlight tetra need a heater?
Yes. Glowlight Tetra need 74–82°F, which is above typical room temperature, so an adjustable heater sized to the tank is essential.
What fish can live with glowlight tetra?
Good tank mates include Neon Tetra, Ember Tetra, Harlequin Rasbora, Honey Gourami, Bronze Corydoras, Otocinclus. Match water parameters first, then temperament, then adult size.
What should you not keep with glowlight tetra?
Avoid Angelfish, Tiger Barb, Goldfish. These are either aggressive towards them, unsafe around them, or need water parameters too far outside 74–82°F and pH 5.5–7.5.