Aeration and gravel pit ponds. True - aeration is not necessary to grow fish in a deep pond. It all depends on the goals for the pond.
Firstly before you believe anyone regarding weather a pond needs aerated or not, oxygen tests should be made during the mid-summer July-August to determine if complete loss of dissolved oxygen (DO) occurs. Many knowledgable people are not really knowledgable. Just becaue they are supposed to be knowledgable does not make them always right about all pond advice. It all depends.
It is truly the exceptional pond where complete oxygen loss does not occur in the deep zone of ponds during mid-summer. Only about two pond situations readily come to mind where a pond will not lose all DO in the deep zone. Very clear water and or rapid water exchange due to infow of deep, underground, feeder springs. Another exception would be a pond with only shallow water (max 7-8ft deep) with high wind exposure; however I do not consider a 8ft pond to have a true deep zone. If a pond does not have at least one of these characters then DO loss in summer is very predictable.
Although if one does not care if the deep water and pond bottom loses all the oxygen and the deep sediments become "lifeless" or dead during mid summer, then YES the pond never needs to be aerated. It always depends. Big fish can be raised in ponds that are not aerated. It is done all the time. The entire fish community including the biggest fish manage to live and grow in the upper oxygenated zone of deep ponds during the periods when oxygen is absent from the deep water. The main disadvantage to not aerating the stratified pond with big fish is the likehood of summer turnover and a partial of total fish kill. Biggest fish usually die first when a summer fish kill occurs.
