The
experiments were carried out in glass aquarium (100
L water capacity) with six replications (30 fish in each
zinc concentration and control). No zinc was put into
the aquarium containing the control fish. The water in
the control and Zn containing aquarium was renewed
everyday in order to minimize decrease in the Zn
concentrations. At each interval of 15, 30 and 45 days
of long-term exposure, six fish were sampled from
each group for determination of zinc in different
organs.