In this study, the lethal concentration and acute toxicity of silver nanoparticles synthesized using aqueous and alcoholic extract of seaweed Sargassum angustifolium that is produced by biological methods were investigated at static renewal condition during 96 hours in common carp in accordance with standard methods (1998) OECD. TEM analysis showed that the average size of the bionanoparticles extracted from alcoholic solution was finer and their toxicity is higher than the particles acquired from aqueous solution.