In intensively cropped rice systems, a fish cropping
cycle usually spans a wet season, ratoon and dry
season crop, about 10±11 months. From the
perspective of fish culture, this period contains
three different environmental conditions. The first
is the dry and wet season rice cropping period, when
fish are free to enter the rice field. The water level at
that time is about 10±20 cm high. A second period
is the rice ratoon period, when water levels can
reach more than 40 cm and in which weeds are
abundant. A third period is the period at the end
and beginning of each rice crop when farmers
prepare their land, seed or harvest rice. At that time
there is no water on the rice field, and fish remain in
the trench.