Control of water quality is the key factor for a successful culture of aquatic animalslike fish, prawn and shrimp. An open water system with sufficient good water qualitymay ensure successful aquaculture. However, if proper quality or sufficient quantityof water is not available, purification of water by eliminating polluting substancesincluding toxic metabolites and growth inhibiting substances which originate mainlyform fish or shrimp excretion and excessive feed is necessary. Under these lowerwater quality conditions there are chances for occurrence of mortalities by diseasesdue to viral, bacterial, protozoal, fungal pathogens. High populations of aquaticanimals can be kept healthy under successful semi-closed and closed systems bymaintaining proper sanitisation. The increased demand in water quality and quantityin shrimp and fish culture has resulted in a growing interest in using water sanitisersand disinfectants.