Acestrorhamphidae

Glowlight Tetra

Hemigrammus erythrozonus

The Glowlight Tetra, or Hemigrammus erythrozonus by its scientific name, is a member of the Acestrorhamphidae family. It gets its name from the bright red-orange stripe running from its head to its caudal fin. These attractive fish, when grouped together, stand out noticeably among other species, and interestingly, their coloration only becomes more intense with age.

Tank
from 60 L (16 gal)
Temperature
23 – 28 °C (73 – 82 °F)
Size in aquarium
4 cm (1.6 in)
Acidity
pH 6–8
Natural rangeRange on the map
  • Guyana

Tank conditions

Plan the tank stocking
Temperature
23 – 28 °C (73 – 82 °F)
Water pH
Slightly acidic (6) – Slightly alkaline (8)
Water dH
Soft (5) – Hard (12)
Water salinity
no salt (freshwater)
Size in aquarium
4 cm (1.6 in)
Lifespan
5 years
Temperament
Peaceful (regular)
Toward small fish
not a predator
Required aquarium volume
from 60 L (16 gal)
Lighting
dimmed
Substrate
sandy (regular, light)
Water flow
weak or moderate
Swimming level
middle level
Feeding
Mixed diet meat + plant-based
Keeping
Schooling usually from 5–6 individuals and more
Jumping
low
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (schooling (usually from 5–6 individuals and more)), footprint, decor and tank mates.

Care and keeping

Description

The Glowlight Tetra is a small species, not exceeding 4 cm in length. Outwardly, it resembles the Black Neon Tetra due to a similar horizontal luminous stripe, however, these are two completely different species. It is easily recognized by its almost transparent body. With age, the distinctive stripe becomes increasingly clear and pronounced.

Habitat

The species Hemigrammus erythrozonus was described by researcher Durbin in 1909. These fish were first discovered in South America, specifically in the Essequibo River, located in Guyana. The Essequibo River, being the longest in Guyana, is home to many species. The tetra typically inhabits the tributaries of the main river channel. Here, the water has a dark brown hue due to the decomposition of organic matter. The fish move in groups, and their diet consists of worms, small crustaceans, and plant matter.

Behavior and Compatibility

The Glowlight Tetra coexists well with other peaceful and small species. Such tankmates include livebearers, small cyprinids and characins, most Gouramis, and peaceful bottom dwellers. The fish feel best when kept in groups of at least 6 individuals.

Care and Maintenance

The Glowlight Tetra is distinguished by its hardiness and unpretentiousness. The main condition for its keeping is water purity. To achieve the necessary water quality, it is recommended to change 30–50% of the volume every two weeks, along with an effective filtration system. Other equipment includes a heater, an air pump, and a lighting system set to dim light. In aquarium decoration, it is appropriate to use several groups of plants, including floating ones, but their quantity should not be excessive. Sandy substrate can be supplemented with artificial driftwood, caves, and other decorative elements.

Diet

Being omnivorous, these fish readily accept both dry commercial and live foods, as well as plant-based options. To ensure optimal balance in their bodies, it's important to offer high-quality dry foods, whether natural or frozen, and occasionally treat them to small worms or bloodworms. Like many Tetras, these aquatic inhabitants prefer to feed several times throughout the day, with each meal typically lasting about 3 minutes.

Breeding and Reproduction

Successful breeding is achieved in a separate aquarium, which allows for optimal conditions and prevents other fish from eating the eggs. For a 40 L spawning tank, a heater and filter are sufficient. Lighting can be dim or even neglected, as the fish and their fry prefer subdued light. The water should be soft, acidic, or slightly acidic. The setup includes a sandy substrate and groups of rooted, fine-leaved plants. Spawning usually begins after several weeks of intensive feeding, when live food is added to the daily diet. The chances of reproduction increase when keeping about 12 individuals – 6 males and 6 females. When the belly of some fish becomes noticeably rounded, it means the female is full of eggs. She, possibly along with a male, should be transferred to a separate tank; it may be necessary to temporarily relocate several pairs. The female lays eggs on plant leaves, pressing her belly against them, with about 10 eggs attached at a time, which the male then fertilizes. After spawning is complete, the parents are removed from the aquarium. Fry appear after 24–36 hours and begin free-swimming on day 3–4. They should be fed micro-food and Artemia.

Diseases

The Glowlight Tetra exhibits resistance to most diseases, provided that the required water quality for this species is maintained.

How to choose

When choosing Glowlight Tetras, prioritize active individuals that swim in a school and display the characteristic bright longitudinal stripe. Avoid fish with signs of emaciation, sunken bellies, fin damage, or atypical spots on the body. In the store, the fish should appear lively, and their coloration should be vibrant and clear. Since this is a schooling species, it is recommended to purchase a group of 6–10 individuals to minimize stress during relocation and adaptation to a new aquarium.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Glowlight Tetra get?

An adult reaches 4 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Glowlight Tetra need?

The recommended volume is 60 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Glowlight Tetra need?

Temperature 23–28 °C, pH 6–8, hardness 5–12 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Glowlight Tetra live?

Around 5 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Glowlight Tetra aggressive?

Temperament: peaceful (regular). Keep this in mind when choosing tank mates.

How many Glowlight Tetra should be kept together?

Recommended setup: schooling (usually from 5–6 individuals and more). Ignoring this is a common cause of stress and disease.

What does Glowlight Tetra eat?

Diet type: mixed diet (meat + plant-based). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Glowlight Tetra?

The scientific name of the species is Hemigrammus erythrozonus, family Acestrorhamphidae. It also appears in the literature as: Hemigrammus erthrozonus.

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Other scientific names and conservation status

Other scientific names
Hemigrammus erthrozonus
Conservation status
Least concernLC