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Rice- fish culture consists of stocking of fish seed in rice
field where rice is the principal crop and fish culture has
to adapt to the conditions and requirement of the rice crop.
The main advantages of this system are reported to be:
• Economic utilization of land both for the production
of rice and fish
• Diversified cultivation; the production in one crop
can be compared with the production of other
• Animal protein, an important component of human diet,
can be acquired by rice-fish culture system
• Rice production is increased by 10-15% (Pradhan, 1979)
due to increased organic fertilization and reduced insect
and pest pressure (Schuster et al 1955)
• Helps in eliminating some of the major weed that pose
threat to rice farming
• Less labour and production costs are incurred in this
system as extra labour cost is compensated by fish feeding
in weed which otherwise require manual weeding.
• It is a beneficial opportunity to obtain better income
for the farmers.
Some of the fish species commonly raised in rice system are
Grass Carp (Ctenopharyngondon idella) and Common Carp (Cyprinus
carpio). These fishes have the habitat of feeding extensively
in phytoplankton, zooplankton and minute algae that are commonly
available to them in the rice field. These fishes grow well
in the rice-fish culture system. Research conducted by National
Warm Water Fish Culture Centre, Geylegphu compared the yield
differences and economics of growing rice as mono crop and
with rice-fish culture system. Further the results at the
trail at this centre indicated that common carp (170-410 g)
had faster growth than the grass carp (30-80g) at the end
of three months. The rice yields were also found to be higher
from rice-fish culture plots. This practice was also found
to control the weed Shochum to a great extent.
Field Setting and Agronomic practices of Rice-Fish Culture
A minimum area of 600m2 is required to allow fish growth.
For the rectangular trench, the stocking rate is 0.6 per meter
square and as the fingerlings grew the size was gradually
increased to 2.5 m2 / fish. In the inlet and out lets, the
wire mesh was netted to prevent mixing of fishes and to regulate
water level and maintain water temperature. A trench of 80cm
wide and 80cm deep made throughout the plot from two sides
to maintain regular water flow and also to ease fish harvest.
A minimum of 6-10cm deep water levels needs to be maintained
in the rice field at all time. The rice was transplanted at
a distance of 15-20 cm plant to plant and a row distance of
20cm. The fish can be reared till the time of the rice maturity
and harvested a week before rice harvest.
The fingerlings can be introduced after 15 days of paddy transplantation.
This gap prevents damage of freshly transplanted rice by fish
especially Grass Carp. Manure/fertilizer application needs
can be applied in the field from time to time for maintaining
sufficient growth of planktons on which the fish feeds. Fish
can be supplemented with maize grit, rice bran and oilcakes.
In addition about 2 kg fresh fodder leaves (Ficus, Napier,
Alfalfa and White clover) fed weekly. The water level of knee
height can be maintained for faster growth of fish as well
as the planktons. The unwanted aquatic weeds like Monochoria
vaginalis, Cyperus difformis etc needs to be removed manually
to facilitate free movement of fish. The fish is harvested
few days (3-5 days) before paddy harvest to dry the plot for
the rice harvest.
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