Fish oygenating their own water works well only if they are perpetual motion perch, not so well with actual fish that have to use oxygen in order to move.

(Proper) aeration is not necessary for a pond in order to have fish and good fishing, but it is one of the enhancements that really helps out both the pond and the fish, by reducing organic sediments and the risk of fish kills.

Heck, is this pond naturally occurring and stocked only by Mother Nature? If not, he's already made it "unnatural".

"Live like you'll die tomorrow, but manage your grass like you'll live forever."
-S. M. Stirling
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