The bioassay was carried out in a square glass tank. The top was covered with mesh net aided by elastic rubber band to prevent the fish from escaping. Each tank size of 36.5 cm by 25 cm by 26 cm contained sixteen fish . After a range – finding test, the concentrations prepared for the experiment were 0 mg/L, 20 mg/L, 60 mg/L, 80 mg/L and 110 /L, with two replicates as described by Rahman et al., (2002).