Nanotechnology has revealed profound possibilities for the applications in applied sciences. The nanotechnology works based on nanoparticles. Among nanoparticles, silver nanoparticles largely introduced into aquatic envi- ronments during fabrication. Which cause severe contamination in the environment specially in freshwater fish. Therefore, the current study was a pioneer attempt to use the animal blood to fabricate AgNPs and investigate their toxicity in Cyprinus carpio (C. carpio) by recording mortality, tissue bioaccumulation, and influence on intestinal bacterial diversity. For this purpose, fish groups were exposed to different concentrations of B-AgNPs including 0.03, 0.06, and 0.09 mg/L beside the control group for 1, 10, and 20 days. Initially, the highest concentration caused mortality. The results revealed that B-AgNPs were significantly (p < 0.005) accumulated in the liver followed by intestines, gills, and muscles. In addition, the accumulation of B-AgNPs in the intestine led to bacterial dysbiosis in Cyprinus carpio. At the phylum level, Tenericutes, Bacteroidetes, and Planctomycetes were gradually decreased at the highest concentration of B-AgNPs