# Giant danio

The giant danio (Devario aequipinnatus) is a species of freshwater ray-finned fish belonging to the family Danionidae. Originating in Sri Lanka, Nepal, and the west coast of India, this species grows to a maximum length of 4–6 inches (10–15 cm), making it one of the largest of the danionins. 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. Their native substrate is small gravel. They are native to a tropical 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 insects, but is also supplemented by worms and crustaceans.
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 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. They spawn in clumps of plants.
A so-called "golden giant danio", sometimes seen, is in reality a partial albino fish. Devario affinis, 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. 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.

## 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.