''Hemigrammus erythrozonus'', commonly known as the glowlight tetra, is a small

tropical fish Tropical fish are fish found in aquatic tropical environments around the world. Fishkeepers often keep tropical fish in freshwater and saltwater aquariums. The term "tropical fish" is not a taxonomic group, but rather is a general term for f ...

from the

Essequibo River The Essequibo River (; originally called by Alonso de Ojeda; ) is the largest river in Guyana, and the largest river between the Orinoco and Amazon River, Amazon. Rising in the Acarai Mountains near the Brazil–Guyana border, the Essequibo flows ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. 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 of the dorsal fin being the same color as the stripe. Other fins are silver to transparent. The glowlight tetra is a peaceful,

shoaling In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling. In common usage, the terms are sometimes used rather loosely. Ab ...

fish. It is larger than the

neon tetra The neon tetra (''Paracheirodon innesi'') is a freshwater fish of the characin family (family Characidae) of order Characiformes. The type species of its genus, it is native to blackwater and clearwater streams in the Amazon basin of South Am ...

, and its peaceful disposition makes it an ideal, and popular,

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 ...

fish. It should be kept with similar sized, non-aggressive species. ''Hemigrammus gracilis'' is a senior

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

. The red-line

rasbora ''Rasbora'' is a genus of fish in the family Danionidae. They are native to freshwater habitats in South and Southeast Asia, as well as southeast China. A single species, ''R. gerlachi'', is only known from an old specimen that reputedly origina ...

('' Rasbora pauciperforata'') of

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

has markings and coloring very similar to ''H. erythrozonus'', but is a member of order

Cypriniformes Cypriniformes is an order of ray-finned fish, which includes many families and genera of cyprinid ( carps and their kin) fish, such as barbs, loaches, botias, and minnows (among others). Cypriniformes is an "order-within-an-order", placed ...

, not a close relative. ''H. erythrozonus'' is a medium-sized tetra growing to , notably larger than both neon and

cardinal tetra The cardinal tetra (''Paracheirodon axelrodi'') is a freshwater fish of the family Characidae of order Characiformes. It is native to the upper Orinoco and Negro Rivers in South America. Growing to about in total length, the cardinal tetra has ...

s. It has a life span of two to four years when kept in good conditions. In the wild, the fish eats aquatic insect larvae.

In the aquarium

''H. erythrozonus'' is readily available and usually inexpensive. Golden and

albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with the condition are referred to as albinos. Varied use and interpretation of ...

varieties are also sold. It is best seen in the

freshwater aquarium A freshwater aquarium is a receptacle that holds one or more freshwater aquatic organisms for decorative, pet-keeping, or research purposes. Modern aquariums are most often made from Transparency (optics), transparent glass or acrylic glass. Typi ...

when kept in subdued lighting with a dark substrate.

Water conditions

The water should be soft to slightly hard, d°GH of 6° to 15°, with a slightly acidic pH of 6.8, in the range 6.0 – 7.5. It prefers a temperature of in the range . The hardiness of this fish allows it easily to adapt to harder water, though soft water is essential for captive breeding.

Nutrition

''H. erythrozonus'' 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.

Shoaling

Like all

tetra Tetra is the common name of many small freshwater characiform fishes. Tetras come from Africa, Central America, and South America, belonging to the biological families Characidae, Alestidae (the "African tetras"), Lepidarchidae, Lebiasi ...

s, ''H. erythrozonus'' is happiest, most active, and most aesthetically pleasing when in a

shoal In oceanography, geomorphology, and Earth science, geoscience, a shoal is a natural submerged ridge, bank (geography), bank, or bar that consists of, or is covered by, sand or other unconsolidated material, and rises from the bed of a body ...

. A minimum aquarium length of will make them more comfortable when swimming. Longer and more spacious tanks are preferred to taller tank setups. 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 tighter 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

. Although they generally shoal separately from neon and

s, they will sometimes

alongside the latter, making an arresting spectacle.

Sexing

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'' breeds similarly to most egg-scattering small fish. It 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 not higher than 2°dCH). Water temperature should be kept between . Adding

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

to the tank or filter will soften water and make it slightly acidic. The tank should have dim or no lighting. Spawning is over fine-leaved plants.

Java moss Java moss is a common name for multiple plants and may refer to: *'' Taxiphyllum barbieri'' *'' Vesicularia dubyana'' Hypnaceae {{Short pages monitor