This study aims to examine the restorative impact of corn cob biochar (CCB) on pendimethalin (PMD)-induced toxicity in Oreochromis niloticus. Fish were divided into four groups: the first control group without treatment, the second group (CCB) exposed to 10 g CCB/L, the third group (PDM) exposed to 0.355 mg PDM/L, and the fourth group (PDM+ CCB) receiving both 0.355 mg PDM/L and 10 g CCB/L for 30 days. PDM exposure resulted in behavioral alterations, low survival rate (73.33 %), hematological and biochemical impairments, increased oxidative stress, suppressed immunity, and histopathological damage in gill, liver, and brain tissues. Cotreatment with CCB significantly alleviated these effects, as evidenced by improved survival rate (88.88 %), hematological, biochemical, and antioxidant-immune parameters and reduced histopathological alterations. In conclusion, CCB demonstrated a promising potential to mitigate PDM-induced toxicity in O. niloticus by enhancing physiological, biochemical, and histological resilience.