Aiming at the problem of low resource utilization rate of solid wastes such as fish feces and leftover baits in aquaponics systems, this study aims to screen lactic acid bacteria with the function of promoting the hydrolysis and mineralization of solid organic matter, providing an effective method for the resource utilization of aquacultural solid wastes. In this study, lactic acid bacteria strains were isolated and purified from the biological filter of an aquaponics system using lactic acid bacteria screening techniques, stress resistance tests, and fish feces and leftover bait fermentation mineralization tests. Environmental stress resistance verification was conducted, and a Lactobacillus amylovorus L4 strain with the performance of promoting solid waste hydrolysis and mineralization was obtained. The research results show that the L4 strain has high sensitivity to multiple antibiotics, as well as good high-temperature resistance and acid-base tolerance. At 50°C and 60°C, the survival rates of the L4 strain reached 97.07% and 83.08%, respectively; at 70°C, the survival rate remained at 29.12%. At pH 5.0 and 9.0, the survival rates were 78.02% and 61.59%, respectively. The results of the fermentation mineralization test showed that the fermentation mineralization effect of the L4 group (added with Lactobacillus amylovorus L4) was better than that of the control group (without bacterial agents). Among them, the mineralization rates of potassium (K) and iron (Fe) elements reached their peaks on day 1 (83.36% and 21.17%), and the mineralization rates of calcium (Ca), magnesium (Mg), sulfur (S), and manganese (Mn) elements reached their highest values on day 5 (14.25% - 96.32%). In conclusion, Lactobacillus amylovorus L4 has high antibiotic sensitivity, strong environmental stress resistance, and a significant effect of promoting the fermentation and mineralization of aquacultural solid wastes, with an optimal fermentation and mineralization cycle of 5 days. This study provides a technical and theoretical basis for improving the resource utilization of solid wastes in aquaponics systems.