This project aims to investigate the mechanisms by which fish schools self-organize, focusing on the relative contributions of visual and hydrodynamic interactions. To explore these dynamics, the experimental study will involve placing fish in a controlled flow environment where their interactions can be manipulated and observed under different conditions. By introducing corridors with transparent walls, the natural hydrodynamic interactions will be disrupted, allowing to isolate and examine the role of visual cues in schooling behavior. The intern will be actively involved in designing the experimental setups, maintaining the flow conditions, and analyzing the behavioral data to draw meaningful conclusions about the interplay between visual and hydrodynamic interactions in fish schooling. Our project also implies numerical approaches of the social and hydrodynamical interactions which will allow fruitful discussions between real life and simulations.