To investigate the effects of starvation and re-feeding on hepatic fatty acid composition and lipid metabolism in mandarin fish (Siniperca chuatsi), fish with an average body weight of (5.57±0.57) g were divided into three groups with three replicates in each group. The control group was fed live bait normally for 0 days (C₀), three days (C₃), six days (C₆), nine days (C₉), and 18 days (C₁₈). The starvation groups were deprived of food for three days (S₃), six days (S₆), or nine days (S₉), whereas the re-feeding groups were deprived of food for three days followed by normal feeding for 15 days (S₃R₁₅), six days followed by normal feeding for 12 days (S₆R₁₂), or nine days followed by normal feeding for nine days (S₉R₉). The experiment lasted for 18 days, during which changes in growth indices, hepatic fatty acid composition, and lipid metabolism gene expression were examined. The results showed that: (1) With prolonged starvation, body weight, liver weight, hepatosomatic index, and liver crude fat content in the starvation groups gradually decreased, significantly lower than those in the corresponding control group (P＜0.05). In the S₉ group, hepatocytes showed vacuolation, and cell boundaries became unclear. After re-feeding, there were no significant differences in body weight, liver weight, and hepatosomatic index (HIS) between the S₃R₁₅, S₆R₁₂, and C18 groups (P＞0.05), whereas body weight and liver weight in the S9R9 group were significantly lower than those in the C18 group (P＜0.05). Crude fat content in the S₃R₁₅ group recovered (_P＜0.05), whereas hepatocytes morphology in the S₉R₉ group was not fully recovered. (2) As starvation progressed, the relative contents of saturated fatty acid (SFA) (C16: 0, C 18: 0), monounsaturated fatty acids (MUFA) (C16: 1n-7, C18: 1n-9), and 20: 4n-6 in the liver of the starvation group gradually decreased, while the relative contents of polyunsaturated fatty acids (PUFA) (C18: 2n-6, C20: 5n-3, C22: 6n-3) gradually increased. In the re-feeding group, the relative contents of all fatty acids were recovered to the levels of the C18 group, except for C20: 5n-3 and C 22: 6n-3, which were significantly higher than those in the C₁₈ group (P＜0.05). (3) As the duration of starvation increased, the relative expression levels of fatty acid synthase (fasn), acetyl-CoA carboxylase (acaca), peroxisome proliferator-activated receptor gamma (ppar-γ), and elongation of very long-chain fatty acids protein 6 (elovl6) significantly decreased, whereas the relative expression levels of carnitine palmitoyltransferase 1Ab (cpt1ab) and acyl-CoA oxidase 1 (acox1) significantly increased (P＜0.05). After re-feeding, the relative expression levels of fasn and ppar-γ in all re-feeding groups, acox1, cpt1ab, and elovl6 in the S3R15 group, and acox1 in the S₆R₁₂ group were recovered (_P＜0.05). These results indicate that MUFA and SFA are primarily utilized in the liver of mandarin fish under starvation conditions, whereas SFA, MUFA, and PUFA contents could be recovered after re-feeding. Starvation promotes lipolysis and inhibits lipogenesis, whereas re-feeding can recover normal lipid metabolism. This research provides fundamental data on the physiological mechanisms of nutritional regulation during starvation in mandarin fish.