There is limited safety information available for most of the chemicals humans are exposed to. To aid in filling this data gap, we need efficient screening methods to estimate the chemicals hazard potential. The ideal model is the embryonic zebrafish. Zebrafish embryos develop rapidly, share 80% gene homology with higher vertebrates, and due to their size, highly amendable to high throughput automation. The zebrafish assays can detect bioactivity at the molecular, phenotypic, and behavioral levels. By adopting new technologies, the efficiency and accuracy of bioactivity identification have improved dramatically and has moved the zebrafish model to be the premier bioactivity screening model for human health hazards.