Atrazine is considered the most common aquatic herbicide used. So, the present study aimed at studying atrazine-induced changes in some biochemical characteristics during early embryonic stages of Clarias gariepinus. These characteristics include two metabolic enzymes, lactate hydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G6PDH), two oxidative enzymes, glutathione reductase (GSH) and superoxide dismutase (SOD), two thyroid hormones, triiodothyronine (T3) and thyroxine (T4), lipid peroxidation (LPO), DNA damage and patterns of protein fractions of different early developmental stages.

Gametes were collected from mature specimens of the African catfish, C. gariepinus from the river Nile. The fertilized eggs were incubated in dechlorinized tap water (pH= 7.7, dissolved oxygen 88-94% saturation, temperature 27-29EC and photoperiod