Danio rerio, commonly known as the zebrafish, is a small freshwater fish native to South Asia. It typically grows to about 2.5 to 4 centimeters in length and is recognized for its distinctive horizontal blue and silver stripes. Zebrafish are popular in aquariums and are often used in scientific research due to their transparent embryos and rapid development. These fish thrive in various aquatic environments, including rivers and streams. Danio rerio is known for its social behavior, often found in groups. Their resilience and adaptability make them an ideal model organism for studies in genetics, developmental biology, and toxicology.