The mechanisms of volatile species formation for hydroperoxylated metabolites of unsaturated fatty acids in grass carp oil were investigated. All oil samples were heated at 110 °C for 8 various durations. The hydroperoxylated metabolites were evaluated by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry, solid-phase microextraction gas chromatography mass spectrometry and conventional chemical indicators. Compared to fresh fish oil, the content of monounsaturated fatty acids and saturated fatty acids with higher oxidation stability in the heating samples was significantly increased (P < 0.05), while the content of polyunsaturated fatty acids was significantly reduced (P < 0.05). A total of 35 triglycerides were determined, of these, the relative content of carbon numbers (CNs) 54, 56 and 58 was dramatically decreased, while CN50 and CN52 were gradually increased. Partial least-squares discriminant analysis indicated that continuous heating had different effects on volatile substances and twelve volatile species variables associated with lipid oxidation from the eight various heating periods were identified. In addition, sixteen oxidized metabolites were identified and their content was significantly increased (P < 0.05), except the 13-HODE, 9-HOTrE, 5-HETE and 12-HETE. The metabolic pathways of grass carp oil under continuous heating were clarified based on critical volatile components and oxidized metabolites, intending to reveal the oxidation paradigm of oil exposed to high temperatures. [ABSTRACT FROM AUTHOR]