This communication explores the early-modern circulation and transformation of water knowledge linked to the Venetian experience. It considers three locally interrelated areas of practical knowledge and scientific enquiry: sea tides, hydrogeology (waterscapes architecture), and ichthyology. I argue that the Venetian context offers a relevant historical case of social circulation of knowledge that involved several actors among whom, the fishermen communities, the Magistrate for Waters (the institution that was deputed to oversee the water management of the lagoon), political authorities, lawmakers, university professors, and court scientists.