Pollution of water resources with agricultural water drainage has a great risk on fish
reproduction. Organophosphrous pesticides such as Malathion and dimethaote are frequently used in
Egypt due to their highly effectiveness for controlling agriculture pests. These pesticides were found
that have endocrine disrupting effect on fish reproduction through lowering sex steroid hormones
(estradiol and testosterone). Endocrine disrupting pesticides also have been implicated in the
impairment of fish fecundity, semen quality, hatchability and survivability of fishes. Sex steroid
hormones, vitellogenin, organosomatic index and histopathology are considered as biomarker tools
used for assessing disrupting effect of pesticides on fish.