Based on the 24, 48 and 72 h of exposure to all concentrations, the G. affinis, O. niloticus and C. gariepinus showed no significant differences on mortality except C. gariepinus at 0.5 ml 1^-1. However, based on the 96 h of exposure to all concentrations 100 per cent mortality of G. affinis, O. niloticus and C. gariepinus was observed and showed no significant differences.

The G. affinis and O. niloticus were the most susceptible fishes among the test organisms. The toxicity tests showed that C. tiglium has the potential to be used as piscicides, which can be an alternate to an expensive and scarcely available imported rotenone for eradication of undesirable fish species present in fish ponds.

Signs of agitated behaviors, respiratory distress and abnormal nervous behaviors including eventual deaths were observed in exposed fish. Control fish neither died nor exhibited any unusual clinical signs.