Healthy C. punctatus (18−20 g in weight; 9−11
cm in length) were collected from local freshwater
bodies in and around Annamalai University,
Annamalainagar. Fish were separately maintained at
27±1°C in 1,000 L tank with continuously aerated and
dechlorinated tapwater (pH 7.2−7.4; hardness 185-
200 mg L-1 as CaCO3; alkalinity 170−175 mg L-1 as
CaCO3) at least one month prior to the experiments.
The laboratory photoperiod was 12 h D: 12 h L. Fish
were fed with boiled chicken eggs and small pieces of
earthworm on alternate days and then 60% water was