Lancang Island is one of the islands located in the Thousand Islands of DKI Jakarta, which contains several groups of Cantang grouper fish farmers. In the implementation and process of fish farming made any risk potential. This study aimed to identify risk sources existence and analyzed these risks and strategies that can be applied to control risks occur and will arise. The research method used direct field observation, interviews, and discussions with Cantang grouper farmers. Qualitative data presented descriptively which discusses stages in the cultivation process. These stages started from site selection to harvesting. Each potential risks analyzed and the potential risks mapped using a fishbone diagram. Quantitative data processed using the Failure Mode and Effect Analysis (FMEA) analysis method. This method assessed each risk that occurs. The FMEA fuzzy assessment resulted that the biggest risk in Cantang grouper cultivation was the fish or seeds will catch disease with a Fuzzy Risk Priority Number (FRPN) of 700 which occurs on the stage where the fish easily get disease. The strategy applied by fish cultivators to control this risk is to pay attention to the fish cycle and maintain the cleanliness of floating net cages (KJA) and ensure the feed quality.