This study investigates the toxicity and bioaccumulation of synthesized zinc oxide nanoparticles (ZnO NPs) in aquatic models, specifically *Artemia salina* and adult zebrafish. The ZnO NPs, with a core size of 32.2 ± 5.2 nm, were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the NPs were assessed using a Zetasizer. The acute toxicity of the NPs was evaluated in *Artemia salina* using the Reed and Muench and Probit methods, with a lethal concentration at 50% (LC50) of 86.95 ± 0.21 μg/mL. Physical malformations were observed in *Artemia salina* exposed to 50 μg/mL of NPs for 96 hours. The total protein and cytochrome P450 contents were measured in *Artemia salina*, showing no significant changes. In zebrafish, the NPs were detected in the gastrointestinal tract, gills, and skin, with the highest concentration in the gastrointestinal tract. The study highlights the suitability of *Artemia salina* and zebrafish as models for assessing the toxicity and bioaccumulation of ZnO NPs, providing insights into their potential environmental and human health impacts.This study investigates the toxicity and bioaccumulation of synthesized zinc oxide nanoparticles (ZnO NPs) in aquatic models, specifically *Artemia salina* and adult zebrafish. The ZnO NPs, with a core size of 32.2 ± 5.2 nm, were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the NPs were assessed using a Zetasizer. The acute toxicity of the NPs was evaluated in *Artemia salina* using the Reed and Muench and Probit methods, with a lethal concentration at 50% (LC50) of 86.95 ± 0.21 μg/mL. Physical malformations were observed in *Artemia salina* exposed to 50 μg/mL of NPs for 96 hours. The total protein and cytochrome P450 contents were measured in *Artemia salina*, showing no significant changes. In zebrafish, the NPs were detected in the gastrointestinal tract, gills, and skin, with the highest concentration in the gastrointestinal tract. The study highlights the suitability of *Artemia salina* and zebrafish as models for assessing the toxicity and bioaccumulation of ZnO NPs, providing insights into their potential environmental and human health impacts.