This paper proposes new evidence about the management of fish resources in the Sacred Lake on the island of Delos (Greece) based on unpublished archaeo-ichthyological data. The specificity of this assemblage lies in the presence of freshwater fish identified for the first time by an archaeozoological study. In agreement with the epigraphic data attesting to fish breeding in the lake, the hypothesis that these fish were acclimatized in this fresh water pond is advanced through the study of historical, archaeological and geomorphological data. The management of these fish resources (species selection, acclimatization, seasonal management, capture) presupposes a degree of proficiency in freshwater fish breeding in Hellenistic times and is the only case study of its kind in terms of the set of sources mobilized.