The Zebra Danio or Zebrafish (Brachydanio rerio or Danio rerio) is a tropical fish belonging to the minnow family (Cyprinidae). Originating in Eastern India, it grows to about 2 inches (6 cm) and lives for around 5 years. There are long-finned and other color forms of this danio.

Like other danios it is omnivorous and a peaceful fish that gets along well with other fish in community tanks. A schooling fish, it prefers to be in groups of 6 or more. Zebra Danios prefer water with a 6.0–8.0 pH, a water hardness of up to 5.0–19.0 dGH, and a temperature range of 64–74°F (18–24°C).

Males have gold stripes between the blue stripes and females have silver stripes instead of gold. An egg-scatterer, danios produce around 100 eggs in a single spawning.

Zebra Danios serve as a common and useful model organism for studies of vertebrate development, because it reproduces very easily, passing from the egg to the larvae stage in less than three days. For genetic research groups, the Zebrafish is an excellent test subject and has already replaced rats and mice in many labs. Zebra danio is one of the few species of fish to have been flown into space (See Animals in space). If researchers modify its genotype at the egg stage, they can see results on its organs barely three days later aided by the transparency of the embryos. A common reverse genetics technique is to knock down gene expression or modify splicing in Zebrafish using Morpholino antisense.

Because of this interest it has been one of the first organisms to have its genome sequenced. The results of genetic engineering in these fishes have been used to produce the Glofish, an aquarium pet with fluorescent pigments.

Other fish also share the name zebrafish.

Diseases

Zebra Danio are susceptible to Oodinium , or Velvet disease .

Feeding

Zebra Danios are omnivorous. Live/frozen flaked foods are suitable, especially brine shrimp. When conditioning zebras for breeding, it's advisable to feed them plenty of fresh foods.

Genetical model organism

Zebrafishes are used as a model organism for genetic analysis of genes. These fishes have the advantage of fast and easy growth in the laboratory. See the external links for more information.

See also

• List of freshwater aquarium fish species

External links

• The Zebrafish Information Network

References

• Zebrafish information network