Glowlight Tetra

Family: Characidae Glowlight Tetra, Hemigrammus erythrozonusHemigrammus erythrozonusPhoto © Animal-World: Courtesy David Brough
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Those fish are so cool when they turn arund.  mathieu

The Glowlight Tetra is a beautiful fish with a glowing orange stripe across the center of its body!

The Glowlight Tetra Hemigrammus erythrozonus derives its common name from the obvious iridescent redish orange stripe down the fish's side. A school of these attractive fish will catch the eye of even the most seasoned aquariast. As they get older, the stripe on the Glowlight Tetra becomes more and more pronounced. They just get more and more beautiful.

This characin is one of the most peaceful tetra species. Like other tetras they are schooling fish and will do best in groups of 5 or more. A group of this size will need a tank that is about 15 gallons or more. They make a great addition to a peaceful community tank. Good tankmates include other tetras, danios, rasboras, and most gouramis. They can also be kept with peaceful bottom dwellers.

This is a durable little fish that adapts well to a variety of conditions and are easy to breed. This makes them a great species for the beginning aquarist. They are most comfortable in an aquarium with loose floating plants to help dim the light, but leaving some open spaces to swim as well. They do not overeat but they do like to eat a small amount of food several times a day. It is best to feed them what they will eat in about three minutes or less, ideally three or four times a day.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Hemigrammus
  • Species: erythrozonus
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Glowlight Tetra - Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Size of fish - inches: 1.6 inches (3.99 cm)
  • Minimum Tank Size: 15 gal (57 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Very Hardy
  • Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
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Habitat: Distribution / Background

The Glowlight Tetra Hemigrammus erythrozonus was described by Durbin in 1909. This species is not listed on the IUCN Red List. They are found in South America in the Essequibo River of Guyana.  The Essequibo is the longest river in Guyana and has many different biotypes throughout the river.  The Glowlight Tetra is normally is found in the heavily forested ares in the tributaries off the main river channel.  The water there is normally stained dark brown from decaying material and is highly acidic. They swim in schools and feed on worms, small crustaceans and plants.

It will be difficult to impossible to find a wild caught Glowlight Tetra for sale in the aquarium trade.  These fish are mass produced for sale.

  • Scientific Name: Hemigrammus erythrozonus
  • Social Grouping: Groups
  • IUCN Red List: NE - Not Evaluated or not listed


The Glowlight Tetra is a small more slim-bodied species of tetra. This fish will reach about 1 1/2 inches in length (4 cm) with a life span of about 2 - 5 years in the aquarium. It is similar in appearance to the Black Neon Tetra with its horizontal stripe that seems to glow, but is a distinctly different fish. They can readily be identified, as their body is transparent. As they get older, the stripe becomes more and more pronounced.

  • Size of fish - inches: 1.6 inches (3.99 cm)
  • Lifespan: 5 years - It can have a lifespan of 2 - 5 years.

Fish Keeping Difficulty

The Glowlight Tetra is a hardy fish that is good for the beginner fish keeper as long as the tank is kept maintained. This fish does well in a variety of different conditions and can be bred fairly easily. This is a great characin for newer fish keepers that want to experience breeding fish.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

Since they are omnivorous the Glowlight Tetra will generally eat all kinds of live, fresh, and flake foods. To keep a good balance give them a high quality flake food everyday. Feed brine shrimp (either live or frozen) or blood worms as a treat. As with most Tetras these fish prefer to eat several times a day. Only offer what they can consume in 3 minutes or less in each feeding.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Glowlight Tetras are not easy to care for provided their water is kept clean. Aquariums are closed systems and regardless on size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the water hardness increases due to evaporation. To combat these ever changing conditions water should be replaced on a regular basis, especially if the tank is densely stocked. At least 25 - 50% of the tank water should be replaced every other week.

  • Water Changes: Bi-weekly

Aquarium Setup

The Glowlight Tetra will do best in schools of 5 or more, so they need and aquarium that is at least 15 gallons or larger. This is a very undemanding species, as can be seen by the wide range of acceptable conditions. They will do best with soft light and peat filtered water. To simulate the black waters that they come from add a mesh bag of aquarium safe peat to the filter. Lighting should be dim and this can accomplished with floating plants,

A biotype setup is the best choice for this tetra and is very easy to put together. The substrate should be made up of river sand. Provide some driftwood branches and twisted roots for decor and areas of retreat. Some dried leaves can be added to stain the water and give them a natural feel. Leaves should be removed and replaced every few weeks. Their natural habitat does not have many plants so it is not necessary to include them.

  • Minimum Tank Size: 15 gal (57 L)
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Low - subdued lighting - Low lighting in a darker tank set up will bring out the best of the iridescence of this fish.
  • Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
  • Breeding Temperature: 82.0° F
  • Range ph: 5.8-7.5
  • Hardness Range: 2 - 15 dGH
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: All - These fish will swim in all areas of the aquarium.

Social Behaviors

The Glowlight Tetra are generally a good community fish. They will do best kept in schools of 5 or more fish. They can be kept with other livebearers, danios, rasboras, other tetras, most gouramis and peaceful bottom dwellers.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes - Will appreciate a school of 5 or more of its own kind.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Threat
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Safe

Sex: Sexual differences

The female is larger and stronger than the male and has a round ventral section. The male is slenderer and has more color.

Breeding / Reproduction

Picture of a Rummy-nose Tetra Photo © Animal-World
Courtesy David Brough

The Glowlight Tetra are egg layers. When they spawn they lock fins, then while clasped they perform a type of roll-over process in the vegetation. Thus the female releases about a dozen eggs at time and the male fertilizes them. Because of this spawning behavior, this is one tetra that must not have too dense a spawning vegetation.

Most successful way to spawn these fish is in groups of 12 with 6 males and 6 females. Feed this group small live foods and nature should take over and spawning will begin. A separate breeding tank will help to get the best number of fry. Keep the tank dimly lit with clumps of spawning mops or java moss so the female has a place to deposit the eggs. A layer of mesh also works as long as the spaces are wide enough for the eggs to pass through and small enough to keep the parents out. The water should be soft and acidic with a pH 5.5 - 6.5 with a temperature of 80 - 84° F. A small air powered sponge filter is all that is really need for filtration. Filtering the water through aquarium safe peat is a good choice.

Once a successful spawn has been achieved remove the parents. Eggs will hatch with in 24 - 36 hours with fry becoming free swimming 3 - 4 days later. For the first few days feed the fry infusoria type foods until they can feed on microworm or brine shrimp nauplii. Fry are light sensitive during the early stages and require it as dark as possible. Also see Breeding Freshwater Fish: Characins for a general description and see Fish Food for Fry for information about types of foods for raising the young.

  • Ease of Breeding: Easy

Fish Diseases

The Glowlight Tetra will resist disease as long as it is provided with a stable environment. In an unstable tank is unstable it will die off very quickly. A good thing about this tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. It is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to provide the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.

The worst fear of a tetra keeper is the Neon Tetra disease, an essentially incurable and a highly contagious disease of unknown origin and cause. It was first diagnosed in Neon Tetras, and so earned its name, but it can actually affect many other species. The 'Neon Tetra Disease' has been identified as a microscopic sporozoan in the genus Plistophora. It shows up on the fish as a spreading spot or blemish beneath the dorsal fin. There have been attempts to cure this disease with the use of Methylene Blue, but it is not always successful, so the disease is considered incurable. This disease has also been spotted on the Neon Tetra Paracheirodon innesi and the Rosy Tetra Hemigrammus erythrozonus.

As with most fish this tetra can be prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Glowlight Tetra is readily available and is moderately priced.


Author: David Brough CFS, Jeremy Roche
Lastest Animal Stories on Glowlight Tetra

mathieu - 2013-10-11
Those fish are so cool when they turn arund.

Nathan - 2013-06-03
I bought 4 glow lights for my 7 gallon tank yesterday and they are so happy. I noticed two of them doing a mating dance for a little bit but there were no signes of eggs. it was wierd. I love feeding them because they dart through the water to get the food and it is so cute. I have one other guppy in the tank and she seems ok with them. she tried to nip them at first but has really calmed down now and has accepted them. Glo light tetra's are by far the best fish i ever got

  • Clarice Brough - 2013-06-05
    They do sound so cute! I love these little tetras too:)
fish boy - 2009-12-30
I love my 3 glowlights very much. When I bought them they're fins were almost gone, but now their fins are back to normal. They are pretty active and look extremely beautiful when they school with my 3 rummynose tetras. Extremely hardy and attack flake food

Glow - 2011-04-07
One of my Glowlight Tetras has a with film covering its eye. Any ideas what it might be? None of my other fish have it

  • Charlie Roche - 2011-04-07
    Check out Animal-World information on Fish Diseases and Treatment. They specify a disease where the cloudy eye is a symptom and recommended treatments.