A fundamental challenge for Neuroscience is to understand how neural circuits process information from the outside world and internal physiological states, to produce versatile but reliable behavior. Two major research challenges are: 1) the complexity and distributed nature of neural circuits; 2) the need for data spanning multiple scales from molecular and activity phenotypes of single cells through to circuit connectivity and population dynamics and finally the behavioral output itself. The goal of the ZENITH ETN, “ZEbrafish Neuroscience Interdisciplinary Training Hub”, is to understand how neural networks mediate perception and behavior. We will exploit the advantages of zebrafish as a small transparent vertebrate with superb genetic accessibility and use cutting-edge technology to elucidate the interactions between molecules, cells and entire networks that ultimately generate adaptive behavior. Our training goal is to create collaborative, interdisciplinary young scientists who can tackle major challenges within neuroscience research. Training in cutting-edge technologies and analytical frameworks will enable this next generation of researchers to perform integrated, multi-scale analyses to elucidate the neural basis of naturalistic behavior. Training is centered on highly collaborative projects between physicists, mathematicians and biologists that will expose ESRs to broad training with academic and industrial partners. Advanced optical methods and genome-editing will be utilized to link molecules to circuits, to map connectivity between cell types across the nervous system and to build computational models of brain activity that will be experimentally tested. Overall ZENITH will help to change the way young scientists are trained in Europe and provide the conceptual, technical and analytical skills needed to take on the challenge of understanding how the beautifully complex circuits of the vertebrate brain control behavior.