["International Journal of Osteoarchaeology, EarlyView. ", "\nABSTRACT\nThe ancient town of Tanais was situated on the right bank of the River Don, near its confluence with the Sea of Azov. It was founded in the late first quarter of the third century bc and has been destroyed by the mid‐third century ad. Excavations in trench XXV of western Tanais uncovered remains of a defensive ditch, several Hellenistic pits, and the western part of the town. These structures contained numerous fish remains and fishing artifacts, enabling researchers to reconstruct the inhabitants' diet during the Hellenistic and Roman periods. The well‐preserved fish remains also allowed for size estimates and insights into fishing techniques. Both Hellenistic and Roman layers contained only freshwater and migratory fish, including four species of sturgeons, wels catfish, cyprinids, perches, and Northern pike—particularly notable given the proximity to the Sea of Azov. There is no evidence of fish product trade. The variations in species composition and fish size distribution suggest changes in the water systems at the turn of the eras.\n"]