<p>The prevalent use of xenobiotics, including waterborne herbicides, can lead to oxidative stress and tissue damages in non-targeted species, such as fish, over time. This study aims to evaluate the toxicity of a newly introduced arylpicolinate herbicide, namely florpyrauxifen-benzyl (FPX), on Nile tilapia (<i>Oreochromis niloticus</i>). The median lethal concentration for 72 h (72h-LC₅₀) was assessed after fish-exposure to six FPX concentrations, spanning from 2 to 4 ppm. The mode of toxicity was monitored by allocating fish into three groups (0, 1/10 LC₅₀, and 1/5 LC₅₀ of FPX) for one and two constitutive weeks. Malondialdehyde (MDA), reduced glutathione (GSH), and nitric oxide (NO) levels, along with superoxide dismutase (SOD) and catalase (CAT) activities, were monitored. Histopathological alterations in gills and muscles were also examined. The current study indicated a low 72h-LC₅₀ value (2.89 ppm) of FPX herbicide on <i>O. niloticus</i>. FPX stimulated oxidative stress by altering activities of antioxidant enzymes. Gills and muscles showed significant histopathological alterations, including degeneration, aneurysm, shortening, and curling of gill lamella, as well as degeneration, edema, infiltration of leukocytes, and necrosis of muscle fibers at both FPX concentrations, with the highest damage observed at the high concentration (1/5 LC₅₀) after two weeks of exposure. The correlation matrix revealed a positive correlation between MDA and NO in gills and muscles, in contrast to a negative correlation with GSH, SOD, and CAT in both organs. Two principal components accounted for 75.92% of total variance. In conclusion, FPX can induce oxidative and histopathological effects on non-targeted species such as Nile tilapia if used improperly. Further studies on other organisms, concentrations of FPX, or durations of exposure are recommended.</p>