Due to great advantages of ozone compared to conventional water treatment methods, ozonation technologies are increasingly used in aquaculture. Implementation of ozone technologies in fish farming enhances competitive edge of producers and farmers. Ozone is efficient in removal of organic substances, pesticides and nitrates. In conjunction with solid particle filters, ozone technologies increase their effectiveness. Unused ozone decays back to oxygen without leaving any chemical residual, and saturating water with oxygen. Ozone destroys complex molecules, which are resistant to conventional biofiltration. In comparison to other water treatment and purification systems, ozone technology poses far less incidental threat to water contamination.