A 10‐week feeding experiment was conducted to estimate the effects of rapeseed meal (RSM) and cottonseed meal (CSM) as a replacement for equal proportions of fish meal and soybean meal for Grass Carp Ctenopharyngodon idella. Two isonitrogenous and isoenergetic diets were formulated; a basic commercial formula was fed to the control (CT) group, while the RSM and CSM diet was fed to the experimental (ET) group. The results showed that the survival rates were 98% (CT group) and 99% (ET group), which were not significantly different. Compared with the CT group, the weight gain rate of Grass Carp in the ET group was significantly decreased; hardness, gumminess, and chewiness of muscle in the ET group showed significant increases; and adhesiveness of muscle was significantly increased. The expression levels of the myosin heavy chain (MyHC*) and myogenic regulatory factor 5 (Myf5*) genes in the muscle of the ET group were significantly increased compared with those in the CT group. Moreover, the expression level of the troponin gene in the ET group muscle was significantly increased compared with that in CT fish. This study indicated that a high proportion of CSM (27%) and RSM (27%) in feed had negative effects on the growth performance and muscle texture of Grass Carp.