Recirculating aquaculture system (RAS) technology is a relatively new system but holds promise, particularly for raising finfish. The system is made up of land-based tanks with water filtering technology that enables the facility to operate in a closed loop. The only outputs are filtered water and waste, though some freshwater systems are able to collect fish/feed waste and use as fertilizer elsewhere, further improving the sustainability of this system. Due to its technology and energy requirements, RAS has high upfront costs, but is increasingly being implemented by new companies. Several producers in Asia are using RAS to grow giant grouper.
The most common method for farming Murray cod uses earthen ponds for grow-out and land-based tanks for hatchery operations. The freshwater, open air ponds host algae which helps in filtering fish waste as well as producing oxygen for the fish. These systems are also typically nearby to crop land, and the nutrient-rich water from the Murray cod farm is used for irrigation. This strategy of circulating and reusing the water means waste does not build up.