In Indonesia vaname shrimp is one of the types of shrimp that has undergone rapid excellence development that is able to adapt to high salinity and may be kept in the high stocking. The quality of the water has a very important role in the success of the cultivation of shrimp. Water as a medium of shrimp's live, which gives the direct effect on health and the growth of shrimp. Quality of water determines the existence of different types of organisms that exist in the ecosystem of ponds, both of shrimp and other biota. Quality of water which is far from the optimal value can cause failure of the cultivar, but optimal quality of water on the contrary can support the growth of shrimp. This research aims to build decision support systems to assist the company in managing water quality in order to get a good shrimp cultivation. The attributes used are water's high, salinity, DO, temperature, pH, alkalinity and attributes of the target size shrimp. Based on the results of the classification algorithm sing C 4.5 obtained accuracy of 76.47%, 72.72% of precision and recall of 88.88%. From this research it is evident that with decision support system algorithm C 4.5 can be used to determine the cultivation of shrimp vaname.