Glowlight Tetra

A Beautiful Choice for Beginners

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 setting. Because they are schooling fish, you'll want to purchase at least six Glowlight Tetras at the same time.

Breed 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 5.8–7.5
Hardness up to 15 dGH
Temperature 74–82 degrees Fahrenheit (24–28 degrees Celsius)

Origin and Distribution

The Glowlight Tetra originates from the Essequibo basin in Guyana and has been found living in the Essequibo, Mazaruni, and Potaro Rivers. Areas of these waters are stained with tannins which make them naturally soft and acidic, ideal conditions for the Glowlight Tetra to thrive. The Glowlight Tetra is also bred in, and exported from, Asia and Germany and was introduced to the aquarium trade in 1933. It was originally named Hemigrammus gracilis, but that was later changed to the current name, Hemigrammus erythrozonus. However, scientists continue to study this fish and may ultimately move it to the genus Cheirodon.

Colors and Markings

The Glowlight Tetra is one of the most popular of all Tetras as it's peaceful and easy to care for. 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, hence the common name of 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 snow 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 are schooling fish; 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 Tetras. Slow moving fish and fish with long fins are safe with Glowlight Tetras. However, avoid Angelfish as they will consider the Glowlights tasty snacks and eat them. Avoid all large fish as well as any fish that are predatory. Fish that are extremely active may prove stressful for the Glowlight Tetra.

Habitat and Care

Glowlight Tetras are most attractive and most comfortable when kept in a darkened tank. Chose a dark substrate and provide plenty of vegetation, but leave some open space for swimming. Add tannins to both soften and darken the water along with floating plants to provide the finishing touch to the perfect Glowlight Tetra habitat. Glowlight Tetras tolerate a wider range of water parameters than similar species, such as the Neon and Cardinal Tetras. Follow these water guidelines:

  • Soft and slightly acidic water
  • Hardness of 6 to 15 dGH
  • pH of about 6.6
  • Warmer temperature in the upper 70s


Glowlights are omnivorous so they will eat all types of foods. It's important to feed small-sized food and vary the diet. They readily accept live foods as well as flakes, freeze-dried, and frozen foods. They will rarely eat food that has fallen to the bottom, so feed small quantities more frequently, as opposed to less frequent large feedings. 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.

Sexual Differences

Female Glowlights are larger bodied and plumper than males. The males are generally smaller and more slender, particularly in the abdomen, which is 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 of peat to soften and darken the water. Keep the water temperature warm, in the range of 78 to 82 F (26–28 C). Low lighting in the tank is necessary; in fact, you can light the tank with ambient light from the room the tank is in. Plant the tank with fine-leafed plants, such as Java Moss. A spawning mop is also suitable in lieu of moss.

Condition the fish with three to five small feedings per day. Vary the diet, including live foods if 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. Some breeders favor placing a spawning grate on the bottom to protect eggs that fall to the bottom.

The eggs are extremely light sensitive, so keep the rearing tank dark. Hatching occurs in approximately one day, and the fry (baby fish) becomes free-swimming in three. At two weeks of age, the fry show silver coloration, and at three weeks they begin to show the trademark glowing line through the middle of the body. Initially, feed the fry infusoria or paramecium cultures, 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 Breeds and Further Research

If you’re interested in similar breeds, check out: