Aquaculture systems typically consist of a cage or net system, or a pond or tank setup. Using a cage or net, the fish will live in an existing water source, usually a lake, but will be contained to make feeding and harvesting easier. Cages, by definition, have rigid sides. However, nets are only rigid on the top. They are no Club Arinna Hotel, but they do allow for water to move in and more freely, which keeps the water quality up and removes waste from the crowded area of fish.
Small ponds and tanks are another way to raise fish. Typically, there is no main water source in these systems. Instead, the water is cleaned and filtered, and then pumped back in. These recirculation techniques allow fish to be raised in a closed environment. In the case of tanks, they can actually be housed indoors in a heated space that would allow the fish to be raised all year around.
Usually, the system will be comprised of a growing tank for the fish, a filtration system, oxygen injector, and then a pump that moves the clean water back into the tanks. Depending on the farm location and type of fish, a water heater may also be used. New water would still need to be added periodically to replace water that evaporated or splashed out of the tanks.
The outlook for fish farming with a recycling water supply is bright, especially year round indoor farming.