Glowlight Tetra Fish Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists

Tetra Glowlight
Kyknos/Wikimedia Commons/CC BY 2.0

The glowlight tetra is absolutely gorgeous and surprisingly easy to care for. Originating in the rivers of Guyana, it is easygoing and peaceful and can survive in a fairly wide range of aquarium environments. Because they are schooling fish, you'll want to keep at least six glowlight tetras.

Species Overview

Common Names: Glowlight tetra, glolight, fire neon

Scientific Name: Hemigrammus erythrozonus

Adult Size: 1.5 inches (4 cm)

Life Expectancy: 5 years


Family Characidae
Origin Essiquibo River, Guyana
Social Peaceful, schooling
Tank Level Mid
Minimum Tank Size 10 gallons
Diet Omnivore, needs small foods

Egg scatterer

Care Easy
pH 5.8 to 7.5
Hardness up to 15 dGH
Temperature 74 to 82 F (24 to 28 C)

Origin and Distribution

The glowlight tetra's origins are in the Essequibo basin in Guyana; they have been found in the Essequibo, Mazaruni, and Potaro Rivers. The river waters of South America are stained with tannins from plant matter decay which make them naturally soft and acidic.

The fish was originally named Hemigrammus gracilis, but that was changed to the current name, Hemigrammus erythrozonus. However, scientists continue to debate whether this fish should be moved to the genus Cheirodon.

The glowlight tetra is bred in captivity, and it is exported from both Asia and Germany. It was introduced to the aquarium trade in 1933.

Colors and Markings

Peaceful and easy to care for, the glowlight tetra is one of the most popular of all tetras. Small and slender, they reach an adult size of only an inch and a half in length. The translucent, silvery-peach colored body of the glowlight tetra is divided by an iridescent red-gold stripe running from snout to tail. The stripe resembles the glowing filament in a light bulb or glowlight. The same iridescent red color is present on the leading edge of the dorsal fin while the anal and pelvic fins are edged in white.

The trademark stripe of the glowlight tetra is shared by a species of rasbora, known as the red line or glowlight rasbora, and the two fish are sometimes confused. However, the two species are not from the same genus. The most obvious difference between the two is the lack of an adipose fin in the rasbora.


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 species of similar size and shape, 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 extremely active may prove stressful for the glowlight tetra.

Glowlight Tetra Habitat and Care

Glowlight tetras are most attractive and also most comfortable when kept in a darkened tank. Choose a dark substrate and provide plenty of vegetation, but leave some open space for swimming. Add tannins to both soften and darken the water, and add floating plants to provide the finishing touch to the perfect glowlight tetra habitat. Glowlight tetras tolerate a wider range of water parameters than similar tetras.

Glowlight Tetra Diet and Feeding

Glowlights are omnivorous so they will eat all types of foods. It's important to feed small-sized food and to vary the diet. They readily accept flakes, freeze-dried, and frozen foods in addition to live foods. Micro-pellet foods are suitable as well as any good quality flake that has been crumbled into fine pieces. Frozen or fresh brine shrimp is readily accepted too. Glowlights will rarely eat food that has fallen to the bottom, so feed small quantities frequently, as opposed to less frequent large feedings.

Gender Differences

Female glowlights are larger-bodied and plumper than males. The males are generally smaller and more slender, particularly in the abdomen. Bellies are more rounded in the female.

Breeding the Glowlight Tetra

Glowlight tetras have been successfully bred in the aquarium, but the process is known to be somewhat challenging. Prepare a separate breeding tank with very soft water of no more than 6 dGH and pH of 5.5 to 7.0; use peat to soften and darken the water. Keep the breeder temperature warm, in the range of 78–82 F (26–28 C). Low lighting in the tank is necessary; ambient light from the room is sufficient. Plant the tank with fine-leafed plants, such as java moss; a spawning mop is also suitable in lieu of moss.

Condition your school with three to five small feedings per day. Vary the diet, including live foods whenever possible. When a female becomes very plump, place her and a male in the breeding tank. When the pair is ready to spawn, the male will dart about the tank after the female, ultimately performing a courtship display in which he flicks his fins and shimmies near the female. When courtship culminates, both fish roll on their backs, the female ejects her eggs and the male fertilizes them.

A typical spawning will produce between 100 and 150 eggs. The parents provide no parental care and will eat the eggs if they get the opportunity, so remove them as soon as spawning is complete. Many breeders place a spawning grate on the tank bottom to protect eggs from being eaten.

The eggs are extremely light-sensitive, so keep the rearing tank dark. Hatching occurs in approximately one day, and the fry become free-swimming in three. At two weeks of age, the fry show silver coloration. At three weeks they begin to show the trademark glow line through the middle of the body.

Initially, feed fry on infusoria or paramecium cultures, and then on finely crushed flake food. Within a few days, you can feed them freshly hatched brine shrimp. Add micro worms to their diet once they grow a bit larger. 

More Pet Fish Species and Further Research

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Check out additional fish breed profiles for more information on other freshwater fish.