The experiment was to study the effect of Armillaria fermented feed on growth performance, digestion, immunity and antioxidant capacity of Cobitistaenis . Add 0 (control group), 6 (test group 1), 12 (test group 2) and 18 mL (test group 3) Armillaria bacteria liquid per kilogram of basic feed, fermented at (20±2) ℃ for 48 h, making four groups of experimental fermented feeds. 360 Cobitistaenis with an initial body weight of (0.92±0.06) g were selected and randomly divide into four groups with three replicates in each group. The experiment lasted for 13 w. The results showed that the crude protein content of fermented feed increased with the increase of the amount of Armillaria bacteria liquid, but the crude fat content decreased. Compared with the control group, the weight gain rate, specific growth rate and fullness of experimental group of loach increased, the feed coefficient decreased. The above indicators of group 2 was the best. The amylase activity in the dried pancreas of group 3 increased significantly ( P <0.05). Dry pancreas trypsin activity in group 2 was significantly increased ( P <0.05). Dry pancreas lysozyme and superoxide dismutase activities in experimental group were both significantly increased ( P <0.05). The total antioxidant capacity of dried pancreas in group 2 and group 3 was significantly enhanced ( P <0.05). The experiment indicates that 1 kg of basic feed fermented with 12 mL of Armillaria bacteria liquid is most helpful to improve the growth performance, digestive enzyme activity, immunity and antioxidant capacity of the [ABSTRACT FROM AUTHOR]