The emergence and spread of antibiotic resistant bacteria brings risks to disease prevention and control efforts. Although the spread of antibiotic resistance has been a hot topic in recent research, information on antibiotic resistance in aquaculture is still lacking. A bacterial epidemic of was investigated in fish farms at Zhuhai, Guangdong province, China from April to December 2018, and a total of 96 strains of spp. were obtained. Among them, 87 strains were identified as strains were tested for resistance to 16 antibiotics and for their virulence in zebrafish using the KB method and challenge tests, respectively. The relationship of antibiotic resistance and virulence was assessed using Spearman correlation analysis. The results were as follows:(1) The percentage of strains resistant to each antibiotic was:Rifampin (98.85%), Madinomycin (96.55%), Erythromycin (95.40%), Penicillin (68.96%), Sulfamethoxazole (58.62%), Norepinephrine (28.73%), Amoxicillin (21.83%), Gentamicin (13.79%), Neomycin (10.34%), Furazolidone (3.45%), Norfloxacin (2.29%), Chloramphenicol (2.29%), Doxycycline (2.29%), Oxytetracycline (1.15%), Florfenicol (1.14%), and Enrofloxacin (0%). The antibiotic resistance spectrum revealed 32 total antibiotic resistant types existed in 87 strains. The Multiple Antibiotic Resistance Index (MARI) was 0.423, indicating that the strains were isolated in an environment with high exposure to antibiotics. (2) The virulence challenge tests showed that the lethality rate of 37 strains was > 80% in zebrafish, accounting for 42.52% of the total bacterial strains tested; the lethality rate of 39 strains was 30%-80% in zebrafish, accounting for 44.83% of the total bacterial strains tested; and the lethality rate of 11 strains to zebrafish was < 30%, accounting for 12.65% of the total bacterial strains tested. This demonstrates that is a high virulence strain. (3) Spearman correlation analysis showed that the virulence of <0.05), and negatively correlated with Enrofloxacin, Florfenicol (<0.01). Bacterial virulence may be related to antibiotic resistance and this relationship can be either negative or positive. We conclude that are highly toxic and multidrug resistant, and their virulence is negatively correlated with antibiotic resistance. This is presumably produced by the additional biological expenditure of bacteria to the acquisition of foreign DNA. Additional studies on this interaction mechanism may provide new data for the evolution of microorganisms and new ideas for bacterial disease control.