In the last years, metal oxide nanoparticles (NPs) are receiving increasing attention due to their different applications. NPs have unique physicochemical properties that differ substantially from their respective bulk materials of the same composition. According to several studies, titanium dioxide (TiO2) nanoparticles (NPs) have short-term risks on Danio rerio (zebrafish). In the present study, we focus on the potential toxic effects that can be caused by a long-term exposure to titanium dioxide (TiO2) nanoparticles (NPs) on zebrafish. The zebrafish, has long been recognized as a useful model organism in ecotoxicology. Zebrafish Wild-type AB strains, were obtained from the Sicilian Center of Experimental Ichthyiopathology (CISS), University of Messina, Italy, where they were kept in a" Fish facilities"(Stand Alone Unit, Tecniplast), a closed-loop system for the continuous monitoring of vital parameters. Adult specimens of …