Bifenthrin (BF), third-generation synthetic pyrethroids (SPs), is extensively used as an insecticide for its higher killing activity, upgraded stability, and lower mammalians toxicity, compared to earlier SPs. The monitoring of high concentrations of BF in aquatic environment addresses a significant concern to aquatics including fish. In the current investigation, O. niloticus fish was subjected to bifenthrin insecticide (BF) at a dose level equal to 1/10 LC50 (0.68 μg/L) for a period of successive 60 days, followed by assessing of BF-induced hepatotoxic and digestive insults through the biochemical and transcriptomic changes. Moreover, the efficiency of parsley (Petroselinum crispum) essential oil (PLO) in two dose levels to mitigate these impacts was evaluated. Our findings showed that BF induced a high rate of mortality and altered the total body composition, serum biomarkers of hepatorenal function and liver glycogen. Intestinal morphological changes were recorded as well as suppression of activity of the intestinal α-amylase, lipase and protease. Oxidative injury was asserted by the recorded elevation of hepatic malondialdehyde (MDA), protein carbonyl, accompanied with depletion of the content of GSH, and repression of the activity of the both antioxidant enzymes (SOD and CAT). In addition, the RT-PCR analysis of stress-mediated genes showed an upregulated expression manner of tumor suppressor protein (P53), Caspase-3, and heat shock protein-70 (HSP-70) in hepatic tissue. Concurrent supplementation of PLO at the both levels in the diet with BF intoxication modulated the recorded deleterious influences in a dose-dependent way. The data from the current study stated the induction of hepatotoxicity and digestive disorders due to BF exposure in O. niloticus fish, and approved the protective efficacy of PLO to be a promising additive to fish feed.