The huge aquaculture industry in China faces serious threats from Aeromonas hydrophila, a pathogenic bacterium that can cause motile septicemia in aquatic animals. This pathogen utilizes AHL molecules to activate quorum sensing and express virulence factors. To combat A. hydrophila, we introduced AHL lactonases from various bacteria to Bacillus subtilis. By degrading AHL, our engineered B. subtilis can reduce the virulence of A. hydrophila and protect aquaculture animals. In the future, we hope that this approach could be scaled up for widespread application, potentially integrating with existing aquaculture practices to provide a sustainable and effective solution against bacterial pathogens.