The giant danio (''Devario aequipinnatus'') is a species of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Danionidae The danionins are a group of small, minnow-type fish belonging to the family Danionidae. Species of this group are in the genera clades ''Danio'' and '' Devario'' (which also includes ''Chela'', ''Laubuka'', ''Microdevario'', and ''Microrasbora ...

. Originating in

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...

, and the west coast of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

, this species grows to a maximum length of 4–6 inches (10–15 cm), making it one of the largest of the

danionin The danionins are a group of small, minnow-type fish belonging to the family Danionidae. Species of this group are in the genera clades ''Danio'' and ''Devario'' (which also includes ''Chela'', ''Laubuka'', ''Microdevario'', and ''Microrasbora'' ...

s. It is characterized by a blue and yellow, torpedo-shaped body with gray and clear fins. In the wild, giant danios live in clear streams and rivers among hills at elevations up to 1000 ft (300 m) above

sea level Mean sea level (MSL, often shortened to sea level) is an mean, average surface level of one or more among Earth's coastal Body of water, bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical ...

. Their native

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

is small

gravel Gravel () is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentation, sedimentary and erosion, erosive geological processes; it is also produced in large quantities commercially as crushed stone. Gr ...

. They are native to a

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

climate and prefer water with a 6–8 pH, a water hardness of 5.0–19.0 dGH, and a temperature range of 72–81 °F (22–27 °C). As surface dwellers, their diets consist predominantly of

exogenous In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It is the opposite of endogeneity or endogeny, the fact of being influenced from within a system. Economics In an economic model, an ...

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s, but is also supplemented by

worm Worms are many different distantly related bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes. Worms vary in size from microscopic to over in length for marine ...

s and

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s. In captivity, giant danios will usually accept most foods. They are a somewhat aggressive fish, and may bully other fish in community tanks. Giant danios appreciate water movement to simulate the motion of the rivers and fast-moving streams of their origins, and prefer to school. Giant danios are also used as dither fish in South and Central American

cichlid Cichlids () are a large, diverse, and widespread family of percomorph fish in the family Cichlidae, order Cichliformes. At least 1,760 species have been scientifically described, making it one of the largest vertebrate families, with on ...

aquariums. The larger cichlids chase and defend their territories against the giant danios, which allows the cichlids to exhibit more natural behavior. As egg-scatterers, danios produce around 300 eggs in a single

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

. They spawn in clumps of plants. A so-called "golden giant danio", sometimes seen, is in reality a partial

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 ...

fish. ''

Devario affinis ''Devario affinis'' is a species of freshwater ray-finned fish belonging to the family Danionidae The danionins are a group of small, minnow-type fish belonging to the family Danionidae. Species of this group are in the genera clades ''Danio ...

'', '' Devario browni'', '' Devario malabaricus'', and '' Devario strigillifer'' were originally deemed synonyms, but are now valid species.

Diet

The main component of giant danios' diet in the wild are flying insects.Gilpin D., Consultant: Schmid-Araya J.,2012. The Illustrated World Encyclopedia of Freshwater Fish and River Creatures. Anness Publishing. This diet is supplemented with aquatic invertebrates such as worms and crustaceans. In captivity giant danios feed on mosquito larvae, chironomous larvae, white worms, chopped earth worms, or commercially available pet food.Dey S., Ramanujam S. N., Mahapatra B. K., 2014. Breeding and development of ornamental hill stream fish ''Devario aequipinnatus'' (McClelland) in captivity. ''International Journal of Fisheries and Aquatic Studies'' 1(4):01–07.

Habitat

Giant danios are found in fast-flowing streams, usually in hilly areas. Giant danios prefer shaded and clear water. They also prefer gravel or sand sediment. Giant danios are shoaling fish, meaning they are found in social groups.

In the aquarium trade

Giant have become an extremely popular aquarium fish over the decades. Their flashy coloration combined with an active swimming style and shoaling behavior have enticed many fishkeepers to include this species in their displays. They are most popular in community tank setups where they are mainly peaceful schooling inhabitants, A varied diet will bring out the best colors and they thrive in groups of at least 6 or more, ideally 8-10 will bring out their most natural behaviors. It is recommended this species be kept in a tank that is at least 48" (appx 4 ft long) and include ample open swimming space. They are known jumpers, so a secure lid is extremely important. Giant Danios are a tropical fish species and require a tanks water temperature to be at least 70 - 80 degrees F. Their lifespan is on average 5-7 years in captivity, and the ideal pH level is anywhere from 6.0 to 8.0.

Reproduction and life cycle

Giant danio breeding can be induced in captivity. In captivity, breeding is induced by increasing water temperature and creating artificial rain. Juveniles begin to resemble their adult form after 65 days of development. Females are larger than males and also possess a more rounded abdomen. Males interested in spawning chase females and ram into their abdomens with their heads.

Distribution

Giant danios are native to the Indian subcontinent and most of Indochina. Their range runs from Pakistan to Cambodia.

Importance to humans

Giant danios are important in the aquarium trade. About 85% of Indian exports of giant danios are wild caught.

References

External links

''Devario aequipinnatus''

''Devario aequipinnatus'' on Fish Mapper
{{Taxonbar, from=Q637325 Freshwater fish of Sri Lanka Devario Fish described in 1839 Taxa named by John McClelland (doctor)