Script 35.11


Keeping fish in your rice fields reduces weeds and insects. Fish manure fertilizes rice and increases rice yield. Fish is also a nutritious and tasty food for you and your family.

If you want to raise fish with your rice you need a supply of young fish. Today we will talk about how you can raise your own baby fish instead of buying them or catching them in the wild. You can always sell what you don’t need.

Newly hatched baby fish are called fry and when they are finger size they are called fingerlings. With a little extra time and care you can have fingerlings to put in your rice paddies and to sell to other farmers. Here is a way to produce common carp (Cyprinus carpio). You will need two ponds, a spawning pond and a nursery pond. Spawning is when adult fish breed and lay their eggs. A spawning pond is a pond where fish can breed and lay eggs. The spawning pond is also where the eggs will hatch into fish fry.

The spawning pond

In a special spawning pond more baby fish will hatch and survive because there are fewer predators and less disease.

When choosing a site for the spawning pond, look for a spot that holds water. Dig a pond about 6 square metres in size and about 70 centimetres deep. Leave the pond empty until the sun has baked the soil completely dry to kill any insects that might eat the newly hatched fry. Once the soil surface is full of cracks, let fresh water into the pond. When the water is at least 50 centimetres deep, the spawning pond is ready for breeding stock.

Choosing carp for spawning

When choosing carp as breeding stock, choose big, healthy adults that are ready to spawn. Females that are ready to spawn have soft swollen bellies. Males that are ready to spawn will secrete a white milky substance when gently squeezed. Choose about ten of the biggest, healthiest females and ten of the biggest, healthiest males. It takes only one day for the fish to spawn.

After one day remove the adults from the spawning pond and put them back in the paddy. If you cannot get adult carp from your paddies or your neighbours, you may have to begin your rice fish farming by buying and raising fingerlings.

Carp eggs hatch in about two days. In a few days the fry will be about the size of an eyelash half a centimetre long and very thin. When the fry are at least a centimetre long, put them in a nursery pond. You can catch them by using a very fine mesh net, or a net made out of loosely woven cloth.

The nursery pond

The nursery pond is a little deeper than the spawning pond, but it is prepared the same way. Dig a pond about 6 metres square and about one metre deep. Let the soil bake in the sun. When the soil is full of cracks, let water into the pond until it is about 70 centimetres deep. The nursery pond must have an inlet for fresh water coming into the pond and an outlet for water to leave the pond. The outlet will prevent the pond from overflowing and washing away the carp fry. Don’t forget to cover the inlet and the outlet with a fine mesh to keep the fry in and the predators out.

Keep the fry in the nursery pond until they are fingerlings. Fingerlings survive better in a rice paddy than fry because they are bigger. Carp fry do well by eating small plants and animals that live in the water, and they will be finger size in six to eight weeks.

When your carp are fingerlings you can put them into your rice paddies or you can sell them to other rice fish farmers. If you have just transplanted your rice seedlings, wait about ten days to three weeks before you put fingerlings in the paddy. This way the rice transplants will be well established and the fingerlings cannot disturb them.

With a little extra effort and minimum expense, you can raise your own carp fingerlings. These fingerlings will do well in your paddies and they will become food for your table and profit in your pocket.


  • This script is based on “Rice fish culture”, pages 69 71 in 101 Technologies from the South for the South, 1992, published and available free of charge in English and French from the International Development Research Centre (IDRC), P.O. Box 8500, Ottawa, Canada K1G 3H9. This booklet features technological innovations in agriculture, forestry, energy, and health that were developed in the south and researched with funds from IDRC.
  • The production of this script and others from 101 Technologies was funded by the International Development Research Centre.
  • This script was written by Sarah Nettleton, Researcher/Writer, Guelph, Canada. It was reviewed by Dr. Saidu Koala, Senior Program Officer, Environment and Natural Resources Division, International Development Research Centre.

Information Sources

  • Farmer proven integrated agriculture aquaculture: a technology information kit, 1992, International Institute of Rural Reconstruction (IIRR), Silang, Cavite, Philippines, and International Center for Living Aquatic Resources Management, (ICLARM), MCPO Box 2631, 0718 Makati, Metro Manila, Philippines.
  • Low external input rice production technology information kit. The Information Service Unit, International Institute of Rural Reconstruction, Silang, Cavite, Philippines.
  • “Rice fish culture”, Greg Chapman and John Sollows, The Sustainable Agriculture Newsletter, Vol. 2, No. 1, March 1990, 16 pages. CUSO, 17 Phahonyothin Golf Village, Phahonyothin Road, Bangkhen, Bangkok, 10900, Thailand.
  • A hatchery manual for the common, Chinese and Indian major carps, V.G. Jhingran and R.S.V. Pullin, 1985, 191 pages. Asian Development Bank and the International Center for Living Aquatic Resources Management, Manila, Philippines.
  • Fish farming, 1982, 72 pages. Inades Formation, 08 B.P. Abidjan, Ivory Coast. Rice fish research and development in Asia, Catalino R. de la Cruz et al., 1992, 400 pages, ICLARM Conference Proceedings 24.
  • A small scale hatchery for common carp, Barry A. Costa Pierce et al., 1989, 42 pages, Institute of Ecology, Indonesian State Electric Company and ICLARM.
  • Farming Systems Research Institute, Department of Agriculture, Bangkhen, Bangkok 10900, Thailand. Sukamandi Research Institute for Food Crops, JI Kakya 9, Sukamandi, Subang, West Java, Indonesia.