The aim of this study was to evaluate the efficiency of polyurethane foam containing silver nanoparticles synthesized by Verbena officinalis leaf extract in controlling of Yersinia ruckeri in treatment of water tanks of rainbow trout farming. Biosynthesis of silver nanoparticles is done with 2mM silver nitrate solution and Verbena officinalis extract. To study antibacterial effects of the produced foams in vitro methods were used, including antibiogram tests on a petri dish, the diameter of inhibition and tube test at different times. Also In vivo methods were used consisting of treatment of water contaminated with bacteria in the presence and absence of fish. Results of mean of diameter of inhibition zone of foam containing 50 and 100mg of Ag-NPs on Yersinia ruckeri were 15.33±1.6 and 14.83 ±0.76mm respectively. Yersinia ruckeri was completely removed after 2h contact with foams of 50 and 100 mg Ag-NPs in water treatment without fish, and after 10min in test tubes at different times. Antibiogram tests showed no colonies in 50 and 100mg Ag-NPs at the bottom of the foam. Water treatment in the presence of fish showed a significant reduction in density of bacteria after 48h contact with filters containing 50 and 100mg silver nanoparticles. Results of this study, as a new production of nano-biofilter, can be used to reduce and control Yersinia ruckeri bacteria in rainbow trout fish farms.