ABSTRACTHybrid striped bass were fed four diets containing 0, 4, 8, and 12% menhaden fish oil (MFO) for 18 weeks during final growth to determine (1) omega‐3 (n‐3) fatty acid uptake and its effect on fish and postharvest quality, and (2) the effects of selected antioxidants on oxidation and sensory quality of fish enhanced with n‐3 fatty acids. Lipid content was significantly higher in the two highest MFO treatments: 3.2, 3.5, 3.9 and 4.4% in the 0, 4, 8 and 12% MFO treatments, respectively. During this study EPA(eicosapentaenoic acid) significantly increased with increasing dietary MFO: 5.4 ± 0.93, 6.9 ± 0.15, 8.0 ± 0.45 and 8.1 ± 0.35 for the 0, 4, 8 and 12% MFO diets, respectively. The following fatty acids in muscle increased 1% or more in fish fed 12% MFO compared to fish fed 0% MFO: 14:0, 16:1n‐7, 22:6n‐3, and total polyunsaturates, total n‐3, and the n‐3/n‐6 ratio. Changes in individual fatty acids in fish muscle reflected the concentrations of fatty acids in the diet. Hybrid striped bass fed 8 and 12% MFO had twice as much n‐3 fatty acids (1.0 g/100 g tissue) as fish culture