Aquaculture in fresh water

Ozone is widely used in freshwater aquaculture as a water treatment tool to improve water quality, reduce organic loading, and lower microbial pressure in production systems. It is especially valuable in intensive and recirculating aquaculture systems, where maintaining stable water conditions is essential for fish health and system performance.

In freshwater systems, ozone is commonly applied to oxidize dissolved organic compounds, reduce fine suspended solids, improve water clarity, and support the removal of waste materials that accumulate from feed, feces, and biological activity. By reducing this organic burden, ozone can help improve overall system efficiency and lessen stress on downstream treatment components such as filtration and biofiltration.

Ozone is also used in freshwater aquaculture for its disinfecting properties. When properly applied, it can reduce the concentration of bacteria, viruses, fungi, and other microorganisms in process water, helping to lower pathogen pressure within the system. This can be particularly beneficial in hatcheries and recirculating systems where water is reused and disease prevention is a major priority.

One of the advantages of freshwater ozonation is that ozone chemistry is generally more straightforward than in seawater. Ozone reacts quickly with organic matter and other oxidizable compounds, and when carefully controlled it can improve water quality without producing the same level of persistent secondary oxidants associated with marine systems. Even so, ozone must still be applied cautiously. Excess dissolved ozone can damage fish tissues, especially the gills, skin, and eyes, and overdosing can lead to stress or mortality.

For this reason, ozone systems in freshwater aquaculture are designed around controlled dosing, proper contact time, and safe removal of residual ozone before treated water returns to the culture tank. Oxidation-reduction potential, or ORP, is often used as a practical operating parameter, although it should be understood as an indirect control measure rather than a direct measurement of ozone concentration.

In freshwater aquaculture, the goal of ozonation is not to sterilize the entire system, but to improve water quality and reduce microbial and organic loading to a level that supports healthier and more stable production. When applied with proper system design and monitoring, ozone can be an effective tool for improving water conditions, increasing clarity, and supporting fish welfare in modern freshwater aquaculture operations.