Aeromonas veronii is a zoonotic pathogen that is commonly found in various aquatic environments and causes serious damage to the aquaculture industry. Anti-virulence strategies based on mutating the virulence factors are important antibiotic alternative methods against A. veronii infection. The type Ⅳ pili, polar flagella, and aerolysin are considered to be the major virulence factors. In this study, we constructed a triple-gene deletion mutant strain (cheZ/mshK/aerA, ΔCMA-AV) and evaluated its potential as a live attenuated vaccine (LAV) candidate. Pathogenicity test showed that the LD