Answer for How much DO requirement in carp culture???

In carp culture, the normal Oxygen requirement is 5-8 ppm that means 5-8 mg/l water.
Oxygen level (ppm) : Effects on fish

3 or < 3 : physiological activities such as growth, reproduction etc. are hampered
1 or <1 : mass died
 
In carp culture, if you use aerator, 20-50% water change weekly, supply supplementary balanced feed regularly, you may stock 10-15 thousand individuals in 100 m x 100 m x 1.5 m pond depend on the size and species of fry.