at 10% of body weight per day. Mortalities and occurrence of
molting were monitored every morning. Dead juveniles, uneaten feed and exuviae molt
exoskeletons. were removed daily. During the experiment, concentrations of ammonia–N
un-ionized plus ionized ammonia as nitrogen. and nitrite–N nitrite as nitrogen. were in
the range of 0.010–0.114 mgly1 and 0.020–0.094 mgrl, lower than the ‘safe level’ of
3.51 mg ly1 for ammonia–N and 2.30 mg ly1 for nitrite–N Chen et al., 1990..