Aquaculture also known as aquafarming of fish, crustaceans, molluscs, aquatic plants, algae, and other organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. There has been a significant shift towards round tanks for fish rearing. Properly designed round tanks with a central drain, moderately sloped floor and proper inlet piping uses gravitational and centrifugal forces to keep themselves clean. The water moving in a circular flow will carry the solids to the central drain from where they can be piped away for separation and re-used or disposed. With a properly designed inlet system, the oxygen rich water will provide just the right current for good muscle tone while distributing new water evenly throughout the tank.