In recent years, use of recirculating technology have given mixed results. There have been some notable large-scale business failures but numerous small to medium-scale setups continue to produce good results. The beginners, prospective aqua-culturists and investors need to be aware of the basic technical and economic risks involved in this type of aquaculture production technology. This presentation and a few more in this series are designed to provide basic information on recirculating aquaculture technology. This course will tell about the importance of Recirculating aquaculture system (RAS) over the pond aquaculture, enumerates required water parameters (dissolve oxygen, ammonia, nitrite, carbon di oxide, pH, alkalinity, temperature, nitrate.) and importance of pelletized feed under critical production considerations, need for RAS, recirculating system designs - the four basic operations which are indispensable for any RAS , components and units for solid waste removal, TAN removal, dissolved oxygen, sanitation practices and pH and alkalinity. This course gives a complete understanding of RAS to begin with on a very simple and presentable way so that even a novice can very well would get aware of the facts and necessary inputs and the onward journey to learn more about the technology enables recirculating aquaculture system will certainly continue to ease on progressively.