The purpose of this study was to see how differences in the C/N ratio affected the microbial decomposition of composite waste from fish and vegetables, which led to the development of composite silage. In this experiment, T1 (100% FW), T2 (100% VW), and T3 (80% FW +20% VW), along with carbohydrate (15% Jaggery) and starter culture Lactobacillus acidophilus (MTCC 10,307), were used for the microbial ensilation. Variations in proximate composition, chemical changes (pH, TTA), the proteinous nitrogenous fraction (C/N ratio, NPN, DH), lipid oxidation (TBARs), and microbial total LAB & Fungal counts (log cfu/g) were investigated on every alternative day during the three weeks of microbial ensilage at room temperature (30 +/- 2 degrees C). A significant (P<0.05) decrease in carbon/nitrogen ratio was observed among T1 (9.36-7.50), T2 (22.31-20.27), and T3 (11.96-7.0) during the ensilage of three weeks in room temperature (30 +/- 2 degrees C). In all the treatments, titratable acidity and LAB (10(7)-10(10) log cfu/gm) show increasing trends which are correlated with the decrease in carbon/ nitrogen ratio and pH value (<4.5) after 72 h of ensilage. Nitrogenous fraction (NPN, DH), and lipid peroxidation product (TBARs) change significantly (P < 0.05) in the following trend T1 > T3 > T2, respectively. Yeast and mould counts were absent in all the samples. The results indicated that the carbon/nitrogen ratio substantially affects the microbial ensilage of fish and vegetable waste. The best combination of the C/N ratio can effectively ensilage these two different stream wastes as animal feed ingredients in the aquaculture industry. [GRAPHICS] .