Adding oxygen into fish rearing waters of hatcheries has been demonstrated to improve water quality for fish. The general relationship is better water produces better fish. This study consists of three segments: 1) evaluate operation of existing oxygenation system at the Rathbun Fish Hatchery; 2) install and evaluate an oxygenation system at the Big Spring Trout Hatchery; and 3) determine the effects of supersaturated oxygen levels on various species of fish. Progress has been made in understanding operation of oxygenation units. Formulas have been developed to predict the amount of oxygen to add to a unit in order to attain a particular level of influent dissolved oxygen. Upon completion of this project hatchery personnel will be able to operate oxygenation systems in the most efficient manner possible without detriment to fish health.