The vertebrate brain is innately equipped with neural circuits that make quick behavioral decisions possible. Elucidating these neural circuits, determining how their master plans are encoded in the genome, and revealing how they can be modified by postnatal experiences will facilitate our understanding of how nature and nurture interact to establish an animal’s behavior. In this review, we explain how transgenic zebrafish can cast insights into the developmental mechanisms and functional roles of the neural circuits that directly and indirectly control visuomotor behavior, by taking as an example a transgenic line Tg(brn3a-hsp70:GFP) enabling visualization of the tectobulbar and habenulo-interpeduncular tracts. These insights emphasize the benefits of applying advanced transgenic technology in zebrafish to future research into this area.