Many countries use cages to grow fish in freshwater ponds and lakes, and in the ocean. The advantages of using cages to grow fish are use of existing bodies of water that are currently not utilized, ease of feeding, ease of stocking and harvesting, and less expense associated with treating or preventing diseases than free swimming fish. Disadvantages are more stressful conditions for some fish species, the possibility of rapidly spreading diseases, and more susceptibility for a fish-kill due to low oxygen conditions. | 
