Hemigrammus erythrozonus – Glowlight Tetra
Hemigrammus erythrozonus was first described by Durbin in 1909. This species is commonly known in Dutch as “Vuurneon.” The Vuurneon belongs to the family Characidae, which includes the characins. The genus name Hemigrammus is derived from the Greek words “hemi,” meaning “half,” and “gramma,” meaning “letter” or “sign.” This name refers to the lateral line of the fish, which is abruptly broken halfway. The species name “erythrozonus” highlights the red band along the side of the body, with “erythro” meaning “red” and “zona” meaning “band.”
Description
The Glowlight Tetra has a slender, torpedo-shaped body. The flanks are silver-gray to silver-white, with a conspicuous, bright red to orange stripe that runs from the head to the base of the tail. This stripe is an important characteristic and even runs over the eye. The dorsal fin also shows red tones, while the other fins (anal fin, pelvic fins, caudal fin) are usually transparent or light-colored. The maximum length is about 4 centimeters.
Sex differences: Adult females are generally rounder in the belly than males, especially when ready to lay eggs. Males are more slender. Behavioral differences between the sexes are not significantly described in the available sources. Young fish (juveniles) resemble adults but lack the full belly of the females and the intense red color. The red stripe develops gradually.
Behavior and Temperament: The Glowlight Tetra is a peaceful and lively schooling fish. It is not aggressive towards other fish but feels most comfortable in groups of at least six, preferably ten or more. Although lively, it can be somewhat shy, especially when kept in small numbers. It swims mainly in midwater but also uses vegetation for hiding places.
Life expectancy: Glowlight Tetras can live for 3 to 4 years in an aquarium. Their exact lifespan in the wild is unknown.
Biotope
The Glowlight Tetra is native only to Guyana, South America. Within Guyana, it lives mainly in the Essequibo River and its tributaries, such as the Potaro, Mazaruni, and other forested areas.
Their natural habitat consists of forested areas along the rivers. The water is colored dark brown by tannins from decaying organic matter, and is therefore acidic. There is a lot of underwater vegetation, and the banks are covered with trees. The bottom consists of river sand and organic matter.
The climate is tropical. However, the water temperature fluctuates, indicating that there may be local variations in water level.
Diet of the Glowlight Tetra (Hemigrammus erythrozonus)
In the wild: Hemigrammus erythrozonus is omnivorous. In their natural habitat, they feed on small invertebrates such as insect larvae, small crustaceans (such as water fleas and daphnia), worms, and additionally on plant material.
In the aquarium: A varied diet is essential. They will accept a variety of commercially available foods, such as flakes, pellets, and tablets. Supplementation with live or frozen foods, such as artemia (brine shrimp), daphnia (water fleas), and mosquito larvae, increases the nutritional value and makes the diet more attractive. Feeding artemia can intensify the stripes’ red color. Overfeeding should be avoided.
The Aquarium
A tank that is at least 60 centimeters long is suitable for a group of six to eight Fire Neons. If you plan to keep larger groups or multiple pairs, a larger tank, ideally 80 centimeters or more in length, is recommended.
The decor should have a dark base, such as dark sand or fine gravel. Use lots of plants, especially along the back and sides of the aquarium, to create hiding places. Floating plants can also contribute to a more natural environment and provide shade. Rocks are not essential, but can be added as part of the decor, as long as they do not have sharp edges that could injure the fish. A few pieces of wood or roots can also give a natural look.
The ideal water conditions include a temperature ranging from 23 to 27°C, a pH level between 6.0 and 7.5, and a hardness (GH) of 2 to 12°dH. It is essential that the water is clean and well-filtered. Regular water changes of 20-30% each month are important for maintaining water quality.
Compatible tankmates include small, peaceful fish like tetras, rasboras, corydoras, and certain gouramis. Avoid larger or aggressive fish that could harm or stress Fire Neons.
Breeding Aquarium and Conditioning
To breed Glowlight Tetras, it is advisable to use a separate breeding aquarium, as the parents may eat both the eggs and the fry. A smaller tank, such as one with dimensions of 45x30x30 cm, is sufficient for this purpose.
Water quality is essential; it should be soft and acidic, with a pH level between 5.5 and 6.5 and low hardness. Osmotic water and peat can achieve softer water.
Proper lighting is also important as the eggs are sensitive to light. It is best to avoid using any lighting or to place the aquarium in a darker location. After the eggs have been laid, you can further darken the tank.
A small sponge filter is adequate for maintaining water quality without being harsh on the fry. Fine-leaved plants, such as Java moss or a spawning mop, offer suitable sites for the eggs to be laid.
To prepare for breeding, parent fish should be well-conditioned for several weeks with a varied diet that includes live foods such as Artemia, Daphnia, and micro worms. Males and females can be kept separate until the females are full of eggs and the males are displaying vibrant colors. At that point, one or more pairs (for example, six males and six females) can be placed in the breeding tank.
The Spawn
During spawning, the colors of Glowlight Tetras become more vibrant. Males display a more pronounced red stripe and exhibit increased activity. The courtship ritual involves the male rapidly swimming around the female while spreading his fins. The eggs are laid among fine-leaved plants, such as Java moss, or on a breeding mop. Spawning typically occurs in the morning after the pair has been placed in the breeding tank the evening before. The Fire Neon Tetra is also an egg layer, scattering its eggs during the process. A typical clutch contains about 120-150 transparent eggs. It is crucial to remove the parents after spawning to prevent them from eating the eggs or the young.
Raising the young Glowlight Tetras
The eggs of Glowlight Tetras hatch within 24 to 36 hours. The young fish begin to swim freely after 3 to 4 days. Since there is no parental care, the parents may eat the eggs and fry if left in the tank, so it’s important to remove them after spawning.
The initial food for the fry consists of infusoria, which are microscopic organisms. As they grow, they can be fed microworms and artemia nauplii (young brine shrimp). While the exact frequency of water changes and fry survival rates are not well-documented, rearing young Glowlight Tetras is often challenging due to high mortality rates. Regular small water changes are crucial to maintain water quality and prevent waste buildup.
Special features of the Glowlight Tetra (Hemigrammus erythrozonus)
- A selected bred albino variety is available in the trade.
- The maximum length is given differently in different sources, ranging from 3.3 cm to 4 cm. This difference is in the explanation of length 3.3 centimeters standard length, is excluding the tail. 4 centimeters length is total length, including the tail.
- The fish are popular in the aquarium trade because of their relatively easy care and attractive appearance. It is important to keep them in groups to promote their natural behavior.
- The water hardness in their natural habitat fluctuates, indicating that they can adapt to some variation in water values.
- Feeding artemia can intensify the red color of the stripe.
- Breeding can be complicated, with a high percentage of young. The use of a laying mop or fine-leaved plants is essential for laying eggs. The eggs are light-sensitive. It is advisable to remove the parents after laying to prevent cannibalism.
- The fish are relatively insensitive to water hardness, but thrive best in soft water.
- They can be kept with many other peaceful fish species, but larger or aggressive fish should be avoided.
Conclusion
The Glowlight Tetra (Hemigrammus erythrozonus) is a relatively easy fish to keep, suitable for both beginners and experienced aquarists. Their peaceful nature and attractive colours make them popular. However, keeping them in groups (at least 6, preferably more) is essential to stimulating their natural behaviour and preventing stress. A well-equipped aquarium with sufficient plants and hiding places is also important.
Breeding can be somewhat challenging due to light-sensitive eggs and potential cannibalism by the parents; however, it is certainly achievable with proper preparation and a dedicated breeding tank. The Fire Neon is known for its striking characteristic: a vibrant red stripe that even extends over the eye, making it a unique and beautiful addition to any aquarium. Overall, the Fire Neon is recommended for those seeking a lively and relatively low-maintenance fish for their setup.
Video
Author
Rickpad – Coby
Copyright images
Ria van der Warf
Peter Maguire
