en fish disease fish disease پژوهشي Orginal research papers Saprolegnia growth on trout eggs is a problem frequently encountered in fish hatcheries worldwide<span dir="RTL">.</span> In the present study silver nanoparticles (Ag NPs) were effectively grafted on the zeolite and bentonite framework using the chemical reduction method. Zeolite and bentonite, silver nitrate (AgNO₃), and sodium borohydride (NaBH₄) were used as inorganic solid supports, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite through an ion-exchange path, in the external and interlamellar space of bentonite at room temperature. AgNO₃ and NaBH₄ were used as a silver precursor and reducing agent<span dir="RTL">,</span> respectively. The Ag/zeolite and Ag/bentonite nano compounds were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR), X-ray powder diffraction (XRD), Energy-dispersive X-Ray spectroscopy (EDX) analysis. The results showed that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antifungal activity of Ag NPs in zeolites and bentonite were investigated against <em>Saprolegnia </em>sp. with different loads of nano composites and exposure time. All Ag/zeolite NCs and Ag/bentonite NCs were found to have antifungal activities. These results revealed that Ag NPs could be used as effective growth inhibitors in different biological systems, for instance in aquatic animal hatchery facilities. Antifungal properties, Saprolegnia, Nano silver, Zeolite, Bentonite, Saprolegnia growth index 1396 1414 http://jifro.ir/browse.php?a_code=A-10-2808-2&slc_lang=en&sid=1 Z. Shokouh Saljoghi zoheirsaljoghi@gmail.com 100319475328460034102 100319475328460034102 Yes Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran O. Farhadian 100319475328460034103 100319475328460034103 No Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran N. Ramezanian 100319475328460034104 100319475328460034104 No Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran M. Mehraban Sangatash 100319475328460034105 100319475328460034105 No Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran