What us the best way to put oxygen in a one acre fish pond?

get some pond plants, get rid of algae and decaying plant / animals in pond

The amount of oxygen in pond water is, in part, a function of the temperature of the water. Hot water holds less oxygen than cold water. So shading the water to reduce the temperature is one way to increase the oxygen level in a pond. Another way is to increase turbulance at the water surface. Add a fountain, water fall or a spitter to cascade the water into the pond. Remember, plants only add oxygen during the day in the presence of sunlight. At night, when there is no sunlight, they use oxygen. And, yes, decaying plant matter and fish consume oxygen. (www.rosepond.com)