It is well recognized that diet influences health, and we are interested in understanding how dietary factors influence development and or susceptibility to other stressors such as environmental chemicals. Because the zebrafish reproduces by spawning and does not have a placenta, the yolk provides the initial nutrients until larva begin to feed. This means what the female eats is deposited into the yolk to support the beginning of the life of the developing zebrafish. It is critical to understand precisely diet composition to explore diet X gene X phenotype relationships. Commercially available diets contain variable and undefined ingredients making the study of a specific nutrient impossible. To address these challenges, we hypothesized that development of a defined diet(s), which is sufficient to sustain zebrafish health, growth, and reproduction, will allow us to study the influence of specific dietary component on health and disease. We have developed defined diets to explore the role of micronutrients in embryonic development and adult disease susceptibilities.