Volatile compounds collected into Tenax TA from fresh uncooked crucian carp ( Carassins auratus ) were analyzed by GC-sniffing and identif ied by GC-MS. The experimental result showed that the specif ic grassy and earthy odor of f ish was correlated with the following C5- C8 carbonyls and alcohols: 1-penten-3-one, 2, 3- petanedione, 1-penten-3-o l, hexanal, ( E, Z)-2, 4-heptadienal, 1-octen-3-ol, 1, 5-octadien-3-ol et al. Among these compounds, hexanal was found to make the most important contribution to the odor of crucian carp. On the other hand, the activity of a lipoxygenase-like enzyme was found in the skin and gill of crucian carp. The crude skin enzyme exhibited act ivity on arachidonic acid, resulting in three C8 compounds.