Blue Danio (Danio kerri)

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Blue Danio
Danio kerri
Blue Danio (Danio kerri)
Name Blue Danio
Name Lat. Danio kerri
Synonym Brachydanio kerri
Family Danios
Family lat. Danionidae
Order Carps
Order lat. Cypriniformes
Origin Thailand
Habitat Streams
Diet Carnivore
pH 6.5-7.5
Behavior Peaceful
Keeping Group
Care Level Moderate
Reproduction Egg scatterer
Breeding Moderately difficult
Life Span 5-7 years
Protection No
Metric Units
Size 5 cm
Temperature 18-26 °C
Hardness 2-12 °dH
Aquarium ~ 120 l
US Units
Size 2"
Temperature 64-79 °F
Hardness 36-214 ppm
Aquarium ~ 30 gal

Distribution and habitat

The island danios are found on some Thai islands (Koh Yao Yai, Puket) as well as in the southern mainland. There they live in streams and small rivers with clear water between rocks and boulders mostly over gravelly bottom.

Maintenance

The aquarium should have a border planting, with hiding and retreat possibilities (roots, stones) and offer a lot of swimming space. A coarse, round gravel as substrate with some foliage covered (e.g. sea almond leaves) and a weak current is ideal.

No ammonia, ammonium and nitrite should be detectable, the nitrate value should not exceed 100 mg/l. To ensure the water quality and oxygen content, a filter and heater adapted to the aquarium size is required, as well as lighting for the species-appropriate day-night rhythm of the animals.

Diet

In nature they feed mainly on insects and insect larvae. The food supply consists of live, frozen and dry food. For a balanced diet, feed once a day with a high-quality, protein-rich dry food (flakes, granules, pellets) as well as cyclops, moina, daphnia, artemia, mosquito larvae, etc. (live or frozen)

It is recommended to feed small portions several times a day. Only feed as much as will be eaten within a few minutes. A regular and varied diet promotes health and increases resistance.

Behaviour and compatibility

They are peaceful, very buoyant and lively fish that are well suited for a community tank with other peaceful fish. They should be kept in a group of at least 8-10 animals.

Basically, only mutually compatible fish species with similar demands on water conditions and water temperature should be socialized.

Sex dimorphism

The males are much slimmer and somewhat more colorful than the more rounded appearing  females.

Reproduction and breeding

They are free spawners. The male usually swims around (drifts) the female in the early morning, which spawns among fine-feathered plants. The larvae hatch after 24-36 hours and swim freely after a few days. The parents do not engage in brood care and should be separated from the fry after spawning, as they are spawn predators.

Fry must be fed several times a day with special rearing food (Artemia nauplii). Breeding is hardly possible in community tanks, as the spawn is easy prey.

Important

Populations from different locations often differ significantly in markings and coloration. The animals from the northern range are usually blue, while those from the south are more yellowish

The tank should be well covered, as they like to jump.

The foliage (sea almond tree, oak, etc.) when rotting promotes the development of microorganisms, which are a valuable secondary food source.

The well-being of the fish should be monitored regularly. Temperature should be checked daily, pH, hardness and nitrate levels at least every 14 days. Regular partial water changes are recommended, even when contaminant levels have not yet reached the upper limit. Sudden changes in water quality should be avoided. Newly introduced fish must be accustomed slowly to the water in the aquarium.

Further literature can be found in your pet store.

References

Text: Werner Winter; Image: Franz Lowak

Source: BMELV (1998): Tierschutzgutachten - Haltung von Zierfischen (Süßwasser); RIEHL & BAENSCH (2006): Aquarien Atlas Bd. 1, Mergus Verlag; ENGELMANN (2005): Zootierhaltung - Tiere in menschlicher Obhut: Fische, Verlag Harri Deutsch

  • Gemäß § 21 Abs. 5 Tierschutzgesetz idgF