Scientific Classification

Species: Danio rerio
Family: Cyprinidae
Order: Cypriniformes

Native Range

South Asia: India, Pakistan, Bangladesh, Nepal, Bhutan.
Introduced to: USA (California, Connecticut, Florida, New Mexico), Colombia, Malaysia.

Habitats

Freshwater habitats: streams, canals, ditches, oxbow lakes, ponds, rice paddies.
Water conditions: near-neutral to somewhat basic pH, temperatures from 16.5 to 34 °C (61.7–93.2 °F).

Description

Appearance: Five blue horizontal stripes on the body, fusiform shape, mouth directed upwards.
Size: Up to 4–5 cm (1.6–2.0 in) in length.
Lifespan: 2–3 years in captivity; up to 5 years in ideal conditions.

Regenerative Abilities

Regenerates heart, lateral line hair cells, photoreceptor cells, and retinal neurons.
Processes Involved: Notch signaling, Wnt signaling, fibroblast growth factor.
Applications: Studied for human heart regeneration, spinal cord healing, and neurodegenerative diseases.

Research Importance

Widely used in developmental biology, gene function, oncology, teratology, and drug development.
Modifications: Many transgenic strains have been developed.

Taxonomy

Genus: Brachydanio.
Sister Group: Danio aesculapii.
Related Genus: Devario.

IUCN Red List Status

Least Concern.

PRACTICE QUESTION

Q. Consider the following statements about Zebrafish:

1.       Zebrafish are native to South Asia.

2.       They are known for their ability to regenerate cardiac tissues.

3.       Zebrafish are classified as "Endangered" on the IUCN Red List.

How many of the above statements are correct?

A) Only one

B) Only two

C) All

D) None

Answer: B) Only two

Explanation:

Statements 1 and 2 are correct.

Statement 3 is incorrect; zebrafish are classified as "Least Concern" on the IUCN Red List.