Hemigrammus erythrozonus
Encyclopedia
Hemigrammus erythrozonus, also known as the glowlight tetra, is a small tropical fish
found in the wild in the Essequibo River
, Guyana
, South America
. It is silver in colour and a bright iridescent orange to red stripe extends from the snout to the base of its tail. The front part of the dorsal fins are the same color as the stripe. Other fins are silver to transparent. The Glowlight tetra is a peaceful, shoaling
fish. It is slightly larger than the neon tetra
, and its peaceful disposition makes it an ideal, and popular, community tank
fish. It should be kept with similar sized, non-aggressive species.
H. erythrozonus is a medium size tetra growing to 4 to 5 cm (1.6 to 2 inches), notably larger than both neon tetra
s and cardinal tetra
s. It has a life span of 2 to 4 years when kept in good conditions.
Glo light, glo-light tetra, and glolight are alternative common names. Hemigrammus gracilis is an older scientific name. The Red-line rasbora
( Rasbora pauciperforata) of Malaysia and Indonesia
has markings and coloring very similar to H. erythrozonus, but is a member of Family Cyprinidae rather than a close relative.
The hardiness of this fish allows it to easily adapt to harder water, although soft water is essential for captive breeding.
. A minimum aquarium length of 60 cm will make them more comfortable when swimming. They prefer a well planted tank for hiding, but with some open water for free swimming. They should be a group of at least four with eight or more to make them feel secure. They tend to swim in smaller groups when a potential predator is present and swim freely when comfortable. They are often bought by aquarium owners to play a 'second fiddle' role to the neon tetra
. Although they generally shoal separately from neons and cardinal tetra
s, they will often shoal
alongside the latter, making an arresting visual spectacle.
Breeding tank set up: A small 40L all glass tank with soft water (hardness up to 8°dGH and carbonate hardness should not be higher that 2°dCH). Water temperature should be kept between 26° and 28 °C (78 F to 82 F) . Adding peat to the tank or filter will soften water and make it slightly acidic. The tank should have dim or no lighting. They spawn over fine-leaved plants. Java moss
(Vesicularia dubyana) or Fontinalis
are suggested but not mandatory, or a spawning mop made of woolen thread. 1 cm glass beads or a spawning grate will help at the bottom to protect eggs from being eaten by adults.
Parents conditioning: Feed the pair kept separately with a variety of live foods, frozen food or dry food for a few weeks. When the female is well rounded transfer the pair to the breeding tank in the late afternoon hours. The spawning will occur in the following morning or the next day, if no spawning behavior is shown after 3 days start over the conditioning of the pair.
Spawning behavior: The male will swim around in a quick manner locking his fins when near the female. During the spawning act both fish roll over, when the female is the upside down position she ejects the eggs while the male fertilises them. Usually 120-150 eggs are dropped in plants and on the bottom. When the pair is done, they will be grazing for the eggs, they should be then removed.
Raising the fry: The eggs are light sensitive, so the breeding tank should be as dark as possible. Some believe the light contributes greatly to the eggs succumbing to fungal infections, though this has more to do with cleanness of tank and water conditions. The fry will hatch in 20 to 25 hours. They should look like small slivers of glass. Fry can be fed with infusoria
, paramecium
culture, crushed flakes, and rotifer
s after they have used all the yolk sack. By the 4th day should be introduced very small portion of newly hatched brine shrimp. The young consume relatively large pieces of live food such as nauplii of brine shrimp. Later microworms can be added to the diet.
Care of the breeding tank: Bottom sediment should always be removed and regular water changes done during the rearing period in order to avoid an accumulation of ammonium and nitrates which can be toxic to the fry. Although large quantities of fry will incubate in waters of low hardness, most of the fry may soon contract non-infectious, constitutional dropsy, and die within a short time. Those who survive will grow well. By the 12th day, they will show signs of a silver coloring. At three weeks of age, the fry will start showing their characteristic orange line and will be a size of about 1 cm. By two months they will be about 2 cm.
Tropical fish
Tropical fish include fish found in tropical environments around the world, including both freshwater and salt water species.Tropical fish are popular as aquarium fish, due to their often bright coloration...
found in the wild in the Essequibo River
Essequibo River
The Esequibo River is the largest river in Guyana, and the largest river between the Orinoco and Amazon. Rising in the Acarai Mountains near the Brazil-Guyana border, the Essequibo flows to the north for 1,010 km through forest and savanna into the Atlantic Ocean.-Geography:There are countless...
, Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
, South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. It is silver in colour and a bright iridescent orange to red stripe extends from the snout to the base of its tail. The front part of the dorsal fins are the same color as the stripe. Other fins are silver to transparent. The Glowlight tetra is a peaceful, shoaling
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
fish. It is slightly larger than the neon tetra
Neon tetra
The neon tetra is a freshwater fish of the characin family of order Characiformes. The type species of its genus, it is native to blackwater or clearwater streams in southeastern Colombia, eastern Peru, and western Brazil, including the tributaries of the Solimões where the water is between...
, and its peaceful disposition makes it an ideal, and popular, community tank
Community tank
Community aquaria are tanks that are designed to contain more than one species of fish. Most commonly they include a variety of species that do not normally occur together in nature, for example angelfish from Brazil, swordtails from Mexico, and gouramis from South East Asia...
fish. It should be kept with similar sized, non-aggressive species.
H. erythrozonus is a medium size tetra growing to 4 to 5 cm (1.6 to 2 inches), notably larger than both neon tetra
Neon tetra
The neon tetra is a freshwater fish of the characin family of order Characiformes. The type species of its genus, it is native to blackwater or clearwater streams in southeastern Colombia, eastern Peru, and western Brazil, including the tributaries of the Solimões where the water is between...
s and cardinal tetra
Cardinal tetra
The cardinal tetra, Paracheirodon axelrodi, is a freshwater fish of the characin family of order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America....
s. It has a life span of 2 to 4 years when kept in good conditions.
Nutrition
It is an omnivore and in the aquarium eats small live, frozen and dry foods and flake foods. The feeding of vegetable matter is suggested to vary the diet.Availability
It is readily available and usually very inexpensive. In some areas, golden and albino varieties are sold.Glo light, glo-light tetra, and glolight are alternative common names. Hemigrammus gracilis is an older scientific name. The Red-line rasbora
Rasbora
A rasbora is a member of a group of small minnow-type fish in the family Cyprinidae . Fish from genera such as Boraras, Microrasbora, Rasbora and Trigonostigma are commonly referred to as rasboras...
( Rasbora pauciperforata) of Malaysia and Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
has markings and coloring very similar to H. erythrozonus, but is a member of Family Cyprinidae rather than a close relative.
Water conditions
They are best seen in the aquarium if kept in subdued lighting with a dark substrate. The water should be soft to slightly hard. d°GH of 6° to 15°. Use a slightly acidic pH of 6.8 in the range 6.0 - 7.5. They prefer a temperature of 25 °C in the range of 22° - 28° °C (72° - 82 °F).The hardiness of this fish allows it to easily adapt to harder water, although soft water is essential for captive breeding.
Shoaling
Like all small tetras, H. erythrozonus are happiest, most active, and most aesthetically pleasing when in a shoalShoal
Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
. A minimum aquarium length of 60 cm will make them more comfortable when swimming. They prefer a well planted tank for hiding, but with some open water for free swimming. They should be a group of at least four with eight or more to make them feel secure. They tend to swim in smaller groups when a potential predator is present and swim freely when comfortable. They are often bought by aquarium owners to play a 'second fiddle' role to the neon tetra
Neon tetra
The neon tetra is a freshwater fish of the characin family of order Characiformes. The type species of its genus, it is native to blackwater or clearwater streams in southeastern Colombia, eastern Peru, and western Brazil, including the tributaries of the Solimões where the water is between...
. Although they generally shoal separately from neons and cardinal tetra
Cardinal tetra
The cardinal tetra, Paracheirodon axelrodi, is a freshwater fish of the characin family of order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America....
s, they will often shoal
Shoal
Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
alongside the latter, making an arresting visual spectacle.
Gender identification
Like most tetras, females are larger and more fat bodied than the more slender male. It may be hard to tell male from female until the fish are fully mature and females fill with eggs.Breeding
H. erythrozonus breed similarly to most egg-scattering small fish. They have been bred in captivity with a moderate level of difficulty.Breeding tank set up: A small 40L all glass tank with soft water (hardness up to 8°dGH and carbonate hardness should not be higher that 2°dCH). Water temperature should be kept between 26° and 28 °C (78 F to 82 F) . Adding peat to the tank or filter will soften water and make it slightly acidic. The tank should have dim or no lighting. They spawn over fine-leaved plants. Java moss
Java moss
Java Moss is a moss belonging to the Hypnaceae family. Native to Southeast Asia, it is commonly used in freshwater aquariums. It attaches to rocks, roots, and driftwood...
(Vesicularia dubyana) or Fontinalis
Fontinalis
Fontinalis is a genus of submerged aquatic mosses belonging to the subclass Bryidae. They are also called Fountain Mosses, Brook Mosses, or Water Mosses....
are suggested but not mandatory, or a spawning mop made of woolen thread. 1 cm glass beads or a spawning grate will help at the bottom to protect eggs from being eaten by adults.
Parents conditioning: Feed the pair kept separately with a variety of live foods, frozen food or dry food for a few weeks. When the female is well rounded transfer the pair to the breeding tank in the late afternoon hours. The spawning will occur in the following morning or the next day, if no spawning behavior is shown after 3 days start over the conditioning of the pair.
Spawning behavior: The male will swim around in a quick manner locking his fins when near the female. During the spawning act both fish roll over, when the female is the upside down position she ejects the eggs while the male fertilises them. Usually 120-150 eggs are dropped in plants and on the bottom. When the pair is done, they will be grazing for the eggs, they should be then removed.
Raising the fry: The eggs are light sensitive, so the breeding tank should be as dark as possible. Some believe the light contributes greatly to the eggs succumbing to fungal infections, though this has more to do with cleanness of tank and water conditions. The fry will hatch in 20 to 25 hours. They should look like small slivers of glass. Fry can be fed with infusoria
Infusoria
Infusoria is a collective term for minute aquatic creatures like ciliates, euglenoids, protozoa, and unicellular algae that exist in freshwater ponds...
, paramecium
Paramecium
Paramecium is a group of unicellular ciliate protozoa, which are commonly studied as a representative of the ciliate group, and range from about 0.05 to 0.35 mm in length. Simple cilia cover the body, which allow the cell to move with a synchronous motion at speeds of approximately 12 body...
culture, crushed flakes, and rotifer
Rotifer
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703...
s after they have used all the yolk sack. By the 4th day should be introduced very small portion of newly hatched brine shrimp. The young consume relatively large pieces of live food such as nauplii of brine shrimp. Later microworms can be added to the diet.
Care of the breeding tank: Bottom sediment should always be removed and regular water changes done during the rearing period in order to avoid an accumulation of ammonium and nitrates which can be toxic to the fry. Although large quantities of fry will incubate in waters of low hardness, most of the fry may soon contract non-infectious, constitutional dropsy, and die within a short time. Those who survive will grow well. By the 12th day, they will show signs of a silver coloring. At three weeks of age, the fry will start showing their characteristic orange line and will be a size of about 1 cm. By two months they will be about 2 cm.