Standing or no action (motionless), swimming, foraging (eating and searching a food
item), attention to servicer and grouping (gathering together) were selected as parameters
of the daily behaviour of carp. Behavioural observations were recorded twice a week
during a period of 1 h before and after the meal in both morning and evening observations
(between 8:00–9:00, 10:00–11:00, 16:00–17:00 and 18:00–19:00 h). The first seen activity
was recorded as determined activity. Each aquarium was monitored separately at 10 min
intervals and noted as counts of fish showing different behaviours. The method of
behavioural observations was based on the methods of ‘‘time sampling’’, ‘‘point sampling’’
and ‘‘scan sampling’’ with some modifications