the fish are inspected at least after 24,48,78 and 98 hours fish are considered dead if there is no visible movement (e.g. gill movements)and if touching of the caudal peduncle produces no reaction dcad fish are removed when observed and mortalities are recorded observation at three and six hours after the start of the test are desirable records are kept of visible abnormalities (e.g. loss of equilibrium ,swimming behaviour, respiratory function, pigmentation, etc.)measurement of pH, dissolvcd oxygen and temperature should be carried out at least daily