In watersheds, medium irrigation projects can be useful for aquaculture even though these water bodies are many times larger than ponds, and are basically built for irrigation or water storage. However, the full potential of these water bodies is not yet realised. Net pens or cages can be used to rear fingerlings in such environments.

It is best to stock advanced fingerlings in large ponds, tanks, and in both small and large reservoirs, since they can better escape predators and competitors. Seasonal ponds, often 0.10-0.15 ha and 1.5-1.8 m deep can be used as rearing ponds for raising advanced fingerlings. Low water levels at the end of the season will make netting and harvesting easy.

Everyone wants advanced fingerlings as early after the rains as possible. They fetch a good price and make marketable fish production possible in seasonal ponds. One way to produce early season advanced fingerlings is to grow them in perennial ponds and store them at high density with minimal feeding for the coming year. Whe such "stunted" fingerlings are stocked into ponds with good feed they grow fast and can be marketed in about 6-8 months.

Common carp is a foreign fish and there are several varieties. The variety used in Western Orissa is the fully scaled carp, which suits the tropical climate. Common carp lives and feeds near the pond bottom and can be grown with the Indian major carps, catla, rohu and mrigal as a 'polyculture' (which means growing many different types of fish together). It can also be grown alone, as a 'monoculture' in rice fields with high dykes that retain water.

In order to provide practical and effective technical guidance for shrimp hatchery management, it is necessary to establish a set of better management practices (BMPs) which underpin an effective hatchery production system. This document is not a complete manual on the management of P. monodon hatcheries but concentrates on the implementation of BMPs for the hatchery covering all of the critical stages and processes in the production cycle, which are currently believed to be causing problems in Vietnamese hatcheries.