Abstract: To investigate the effects of replacing soybean meal with peanut meal on the growth performance and intestinal health of paddy field carp “Ruyuan No.1”, 120 individuals with similar size were randomly divided into two groups with three replicates. An 8-week feeding trial was conducted, with the experimental group receiving a diet in which 50% of the soybean meal was replaced with peanut meal, while the control group was fed a standard diet. Comparative analyses were performed on growth performance, intestinal morphology, digestive enzyme activity, transcriptome profiles, and microbial diversity. The results showed that: (1) The experimental group exhibited significantly higher weight gain rate and specific growth rate (P<0.05), along with a significantly lower feed conversion ratio (P<0.05) compared to the control group; (2) Intestinal lipase activity was significantly increased in the experimental group (P<0.05), while villus morphology showed no significant differences; (3) Transcriptome analysis revealed that differentially expressed genes in the experimental group were significantly enriched in fatty acid metabolism-related pathways, including fatty acid metabolism, fatty acid degradation, and fatty acid elongation pathway. This suggests that peanut meal may enhance lipid utilization by regulating the expression level of genes associated lipid metabolism; (4) Microbial diversity analysis revealed significantly higher Shannon and Simpson indices (P<0.05) in the experimental group, accompanied by increased abundance of Firmicutes and reduced abundance of potential pathogens like Aeromonas; (5) PICRUSt2 functional prediction demonstrated that the relative abundance of lipid metabolism pathways were significantly higher in the experimental group at the secondary functional level. In conclusion, replacing 50% soybean meal with peanut meal significantly improves growth performance, optimizes gut microbiota structure, and enhances lipid metabolism in paddy field carp “Ruyuan No.1”, providing theoretical support for high-quality breeding and soybean meal reduction strategies in aquaculture.