Question

Give merits and demerits of fish culture..

Answer 1

i.Increase in organic fertilisation by fish excreta.
ii.Reduction in the number of harmful insects whose larvae are eaten by fish.
iii.Reduction of rat population due to increase in water level. 

Answer 2

BETTER TILLERING OF THE RICE SEEDLINGS DUE TO THE ACTIVITY OF THE FISH.
CONTROL OF ALGAE AND WEEDS.

ADDITIONAL COSTS ARE INVOLVED IN FERTILIZING AND FEEDING THE FISH.
THE NEED OF RICE VARIETY TOLERANT TO DEEP WATER AND AT LOW TEMPERATURE.

THE FIRST TWO ARE ADVANTAGES AND THE OTHER LAST TWO ARE THE DISADVANTAGES........