Due to the COVID-19 pandemic, the use of high-efficiency particulate air (HEPA) filters in air purifiers has been widely employed to reduce the transmission of the COVID-19 virus. The existence of the heavy metals silver (Ag) and copper (Cu) in HEPA filters will adversely affect both water quality and the survival of aquatic organisms. Further analysis is required to assess the effects of using HEPA filters on environmental pollution and identify any associated adverse effects. This study investigated the impact of HEPA filter exposure on the histopathology of the gill and stomach, as well as the leukocyte profile in common carp (Cyprinus carpio). In brief, common carp samples measuring 8– 9cm in length were subjected to various concentrations of HEPA filters over a duration of 96 hours. The concentrations tested included a control group, as well as concentrations of 5, 10, 20, 30, and 40%. The study revealed that the use of a HEPA filter on common carp had a substantial impact on the leukocyte profile of Cyprinus carpio. Specifically, it caused a considerable decrease in the number of leukocytes at a concentration of 40%, resulting in a reduction of around 11.3 cells/ mm³. Particularly, there was a considerable increase in both total leukocyte count and phagocytosis activity at a concentration of 10% of the HEPA filter. In addition, the HEPA filter induced oedema, hyperplasia, congestion, hypertrophy, fusion, hemorrhagic, and lysis in the tissue structure of the gills. These effects were found at concentrations of 20, 30, and 40%, resulting in a total damage of approximately 12, 28.6, and 66.3%, respectively. The HEPA filter causes hemorrhagic, congestion, and lysis in the stomach organ, resulting in total damage of approximately 7, 13.3, and 32%, respectively. The HEPA filter induces significant alterations in the gill and stomach tissue, with concentrations ranging from 50– 60%.