The inhibitory effect of silver nanoparticles on the bacterial fish pathogens, Streptococcus iniae, Lactococcusgarvieae, Yersinia ruckeri and Aeromonashydrophila

isolates) the results showed that the MBCs were in a range from more than 10 µg/ml to 0.62 µg/ml 30-90 minutes post-inoculation. Also, the range of MBCs for was 0.31 µg/ml to less than 0.15 µg/ml, while the range of MBCs for was from 2.5 to 0.62 µg/ml 30 to 90 minutes post-inoculation, respectively. Generally, the bacterial growth for these bacterial species was reduced from 1 × 10 cells/ml to no growth compared to initial inoculums of 10 cells/ml during 90 minutes after exposure to silver nanoparticles. No remarkable change was found in the bacterial count for the control samples (PBS without silver nanoparticles) during the experiment. silver nanoparticles, , , , , MBC. Streptococcus iniae Lactococcus garvieae Yersinia ruckeri Aeromonas hydrophila.