when the opercula movement and tail beat stopped and the fish no longer responded to mechanical stimulus (touch). Four repli-cates were performed for each test concentration along with one replicate of untreated controls; data were also used to calculate the LC50 value. Similarly bioassay was also carried out against O. niloticus, which was determined 1, 2, 3, 5, and 7 d after testing. The concentration of leaf aqueous leachate was expressed as the ratio between water and leaf weight.