The study aims to investigate the synergistic antioxidant effects of the phenolics present in Mentha piperita (MP) against arsenic trioxide-induced oxidative stress, biochemical alteration, and cyto-genotoxicity in the fish, Channa punctatus. The phenolic composition of MP estimated by HPLC-PDA analysis reveals the presence of phenolics, viz., ascorbic acid (Rt = 2.763 min.), rutin (Rt = 12.597 min.), caffeic acid (Rt = 18.304 min.), quercetin (Rt = 26.731 min.), luteolin (Rt = 42.709 min.), and hesperetin (Rt = 49.525 min.). The experimental setup consists of four groups (G1-G4) with a density of 12 fish in each. The fishes in G1 served as the control group, whereas the fishes in G2 were exposed to 81.73 mg/L of As