Even with fish I'm sure you would be fine. I aerate my well water because my pond is quite small and is a "flow through pond." If i was running the same water directly into my .62 acre pond I would not be concerned. By the time the well water would diffuse into the rest of the pond it would be fine.

If it's cool where you are at I would not worry about D.O. However you should get at least 5 ppm.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.