Since George Streisinger pioneered his research using Zebrafish (Danio rerio) at the University of Oregon in 1972, Zebrafish have become a popular animal model. As a vertebrate model organism amenable to scalable screens, the Zebrafish has long been touted as having the potential to deliver new drug candidates. In the past few years, drug candidates discovered in Zebrafish have finally begun to reach human trials, suggesting that their potential may be turning into reality. Zebrafish is an ideal model organism for vertebrate development because it combines the best features of all the other models. Like the frog, zebrafish embryos develop externally and can be viewed and manipulated at all stages. However, the zebrafish embryo is more straightforward than the frog; it grows faster and is transparent like worms and fruit flies. Danio rerio is a suitable model to study embryology. Its small size, external fertilization, and fast development make it an ideal model species for vertebrate developmental biologists.

As vertebrates, they share a high degree of sequence and functional homology with mammals, including humans. Due to the conservation of cell biological and developmental processes across all vertebrates, studies in fish can give great insight into human disease processes. As mentioned, Zebrafish also provide researchers with a high degree of scalability and phenotypic richness. The ability to screen the whole organism grants scientists access to various complex phenotypes relative to disease. In a recent review, Swinney and Anthony found that approximately two-thirds of the first-in-class drug developed in the last decade was based on the phenotype-based method instead of the typical target-based approach (Nature Review Drug Discovery, 2011).