Although the common carp grew unevenly, those in the experimental plots had reached a fairly high level of growth. In the comparative ponds where fish grew in a natural environment, maximum weight was 169 g, with 19 cm body length and 23 cm total length. Because rice was planted, the bottom organisms had a rich supply of food. But because the pond leaked, water had to be constantly replenished, which reduced the level of fertilization. This change corresponded to good growth of bottom-living common carp and crucian cap, and poor growth of tilapia.
Rice planted in a shallow lake increases the productive surface area, oxygen, and food.
These factors promote the growth of common carp. Because the volume of water is greater than in rice paddies, it is suitable for raising marketable common carp. The planting of deepwater rice will help create conditions that will turn lakes into highly efficient fishery bases for a variety of fish species. The shallow waters of lakes provided good fertility, temperature, and sunshine. The open expanses of water are deep and can hold large numbers of fish.