Hemigrammus erythrozonus, commonly known as the glowlight tetra, or red neon, is a small tropical fish from the Essequibo River, Guyana, South America. It is silver in color, and bright iridescent orange to red stripe extends from the snout to the base of its tail, the front of the dorsal fin being the same color as the stripe. Other fins are silver to transparent. The glowlight tetra is a peaceful, shoaling fish. It is larger than the neon tetra, and its calm disposition makes it an ideal and popular community tank fish. It should be kept with similar-sized, non-aggressive species. Hemigrammus gracilis is a senior synonym. The red-line rasbora (Rasbora pauciperforata) of Malaysia and Indonesia has markings and coloring very similar to H. erythrozonus, but is a family member Cyprinidae, not a close relative.
H. erythrozonus is a medium-sized tetra growing to 4 to 5 cm (1.6 to 2 inches), notably larger than both neon and cardinal tetras. It has a life span of two-four years when kept in good conditions.
The Glowlight Tetra glows like a lamp when lighting conditions are just right. The colorful, neon red/orange stripe shows up best when the aquarium lights are dimmed. For maximum visual effect, keep Glowlight Tetras in groups.
Glowlight Tetras adds beauty to a planted aquarium; the plants, in turn, will provide hiding places for the fish. Rocks and woods also help mirror its natural habitat. It lives in slightly acidic water and will do best when the water parameters are kept constant. Glowlight Tetras are bench fish and are very interesting to watch in action when kept in odd numbers of five or more.
Life span: 2-4 years
Size: 4 to 5 cm (1.6 to 2 inches)
Minimum Tank Size: 10 gallons
Diet: Omnivore, needs small foods
pH: 5.8 to 7.5
Hardness: up to 15 dGH
Temperature: 74 to 82 F (24 to 28 C)
Tank Size for Glowlight Tetra
The aquarium is a base of 100 cm x 40 cm, suitable for a group of 10-15 specimens, to respect its gregarious behavior. The aquarium must be set up with submerged branches and floating vegetation: the more hiding places there are, the less shy the fish will be. Optimal lighting is moderate, so the fish do not experience stress and show their best colors. Filtering on peat, or treating the water outside the tank always with peat, is recommended to amber the water.
Hemigrammus erythrozonus can be introduced in plant aquariums, provided that there are hiding places and shaded areas, and that the light intensity, in general, is not excessive.
A monospecific aquarium of Hemigrammus erythrozonus is not to be underestimated. A numerous school of these characins swimming together shows the species’ character at its best as being a sight for the eye.
Glowlight Tetra Diet and Feeding
Glowlight Tetras will accept many small foods such as brine shrimp or daphnia, freeze-dried bloodworms and tubifex, micro pellet food, and a portion of high-quality flake food.
Glowlight tetras like their own kind; keep them in groups of at least a half-dozen or more. You can also keep them with other small peaceful fish, including other small tetras, barbs, danios, cory catfish, and peaceful loaches. Although they are a schooling fish, they will generally not school together with other species. This is true even with similar size and shape species, such as the neon and cardinal tetra. Slow-moving fish and fish with long fins are safe with glowlight tetras.
However, avoid angelfish as they eat glowlights. Avoid all large fish as well as predatory species. Additionally, any fish that are incredibly active may prove stressful for the glowlight tetra.
Sexual dimorphism and reproduction
In Hemigrammus erythrozonus, the sexual dimorphism is very little accentuated, with the male slightly more colored and tapered than the female. The reproduction of Hemigrammus erythrozonus is not incredibly challenging to obtain in captivity. It is not rare that it reproduces in the main aquarium without particular interventions by the aquarist, even if, in this situation, part of the fry are preyed on by the parents themselves in proportion to the number of hiding places that the plants and furnishings offer. However, to increase a larger fry, the ideal solution is to set up a small aquarium with a minimum size of 45cm x 10cm x 10cm.
The set-up will be completed with driftwood and floating vegetation (or mops) to provide Hemigrammus erythrozonus with a substrate in which to lay. Alternatively, isolate the tray’s bottom with a medium-sized mesh, large enough for the eggs to fall, but tight enough not to allow parents to pass.
The water in the breeding aquarium will be soft and acidic, with pH values between 5.5-6.5 and GH values between 1 and 5. The temperature will be between 26 ° C and 28 ° C. To reach these conditions, it is essential to use peat and osmosis water. An air filter proves to be the ideal choice due to its light current, ensuring the fry’s survival.
Among the various options, both to use a small group of adults of Hemigrammus erythrozonus (in the equal male-female ratio), or to choose a pair, formed by a female with a well-rounded belly and a brightly colored male, both in good health. Once the reproducers have been selected, it will be necessary to condition the specimens to stimulate them to reproduce, increasing the ration, and integrating with live food (daphnia, artemia). This increase in resources at the same time as the change in values starts the courtships.
In both cases, the deposition should take place within 24-48 hours of the start of the courtship. A female of Hemigrammus erythrozonus lays 120 to 150 eggs in normal conditions. Once spawning and fertilization have taken place, the adults are moved to the breeding aquarium. The fry, after hatching, comes to free-swimming within 3-4 days. They should be fed with infusoria or other microscopic foods until they are large enough to accept newly hatched brine shrimp or other food. In an emergency, finely crumbled or chopped frozen food can be used as a fallback. During the first periods after hatching, the eggs and fry have been sensitive to light, so it is advisable to keep the tank in a dimly lit place.