Aquaculture has developed in the enclosed bays and coves along Japanese coast since the 1970s, and the total catch reached approximately 1.2 million tons per year by 2007. However, many fish farms are suffering from a deterioration in water quality. To keep DO conditions of the farms is one of the most serious tasks for sustainable development. Two different measures have been adopted recently for the management of water quality of the farms. One is to move the farms to offshore areas in the open seas to increase water exchange, and another is to develop a new technique to increase DO supply to the water of the present farms in the enclosed coastal seas with microbubble injectors. In this review, I focus on recent achievements of microbubble techniques for aquaculture, and refer to the sustainable development of fish farming in the enclosed coastal seas with this technique.