ILipomas are soft tissue mesenchymal benign tumors divided into two groups: infiltrative and non-infiltrative. In an outside examination of the body of cultured European seabass (Dicentrarchus labrax) obtained from an inland fish farm located in the Turkish Aegean Coast One tumor-like structure was observed on the dorsal side of the back, leading to deformation of the skin surface. It had been not reported in clinical findings and data for diseases and mortality in the fish farm. In the histopathological examination, the tumor (neoplasia) was diagnosed as a subcutaneous infiltrative lipoma. Histologically, the mass was characteristic of a benign tumor, which constituted well-differentiated adipocytes, showing a tendency to invade the underlying musculature. This study described for the first time lipomas in cultured sea bass in Turkey, which could be used to extend the existing information about benign tumors.