This study examines the potential of iron nanoparticle-coated copper oxychloride in mitigating its toxic effects on earthworms, a key component of sustainable agriculture due to their role in enhancing soil quality and promoting plant growth. While earthworms and their coelomic fluid play a crucial role in enhancing soil health and promoting plant growth. Copper oxychloride, a commonly used fungicide, induces oxidative stress by disrupting antioxidant defense mechanisms in living systems. Through probit analysis, the median lethal concentration (LC50) of copper oxychloride was determined to be 2511.9mg/kg. Artificial soil was treated with copper oxychloride at 60% and 80% of LC50, but the addition of iron nanoparticle-coated fungicide successfully reduced earthworm mortality to 0%. These findings offer promising insights into protecting non-target organisms from fungicide toxicity while maintaining agricultural productivity. The findings present a potential breakthrough in sustainable agriculture by demonstrating how nanotechnology can mitigate the harmful effects of fungicides on essential soil fauna. The use of iron nanoparticle-coated fungicides not only protects earthworms but also offers a path to maintaining ecological balance and enhancing crop productivity without compromising soil health.