Farmed large yellow croaker fish have stronger fishy smell and less tender texture than wild-caught ones, mostly caused by the high fat accumulation from aquaculture feeding patterns. To improve the commercial value of fillets, this study investigated a mild subcritical fluid treatment with subcritical butane (SBE) and dimethyl ether (SDME). Changes in the chemical compositions, volatile flavor compounds (VFCs) and protein denaturation were determined for 1-5h treatments. The results showed 24% and 44% defatting levels under SBE and SDME treatment, respectively. GC-MS showed that SDME could induce a significant reduction of total VFC content, especially for the dominant aldehydes. There was less n-nonanal (14.65-40.13mg/kg) and octanal content (1.67-7.21mg/kg), no detection of trans, trans-2,4-decadienal in the SDME treated samples in comparison to those treated with SBE. The results showed that SDME treatment for 3h had the best defatting effect, good deodorization effect and less degradation of fish protein.