Bottom soil plays an important role in determining the productivity of fish ponds by providing sustenance to fish food organisms and, thereby, the growth of fishes. The behaviour and response of different nutrient inputs, used for improving the productivity of such culture system, are also influenced largely by the nature and properties of the pond soils. The book provides some basic information about the methods of assessing and also maintaining threshold levels of different plant nutrients in fish ponds through soil system based approach for increasing their productivity.