The water was kept between 10 and 15 cm. All
fields were stocked with O. niloticus, C. carpio,
B. gonionotus and T. pectoralis. Stocking data can
be found in Table 1. Additional data can be found in
Tables 2 and 3. During the rainy season in 1999,
we also stocked some Osphronemus goramy LacepoÃde
at a rate of 6.4 fish 10±3 m2. All fish were stocked at
about 20 days after rice seeding. One day before
seeding, trenches of all plots were treated with
15 p.p.m. Derris root (5% rotenone) to eradicate
wild fish. A 5-mm screen at the field water inlets
and a 10-mm screen at the main water gate of the
station helped prevent indigenous fish and aquatic
predators from entering the fields.