I did an interesting experiment this weekend. Fish have been feeding well. I am very slowly easing up the aeration system as it's relatively new. At 2 hrs/day, 1-3 am. I measured water temps and it was 76 at 1' and 70 about 12' down (not exactly sure where the thermometer landed out there). I decided to run the aerator for 2.5 more hours Saturday afternoon when it was in the 90s. Right afterward I measured temps and it was 74 degrees top and bottom, so I concluded it was pretty mixed out. This is a shaded ravine, so I don't expect 80s.

I also noted an oily film with surface bubbles that had been pushed out from the aerator. When the aerator shut off, the film started heading back to the centerpoint. Shortly after, it was feeding time. It was hot, sunny and this film was on the surface in the feeding zone. I took the film to be some of the badness from the bottom that had been brought up as it is not normal. There was none of the awful smell you get with really stratified water. Would have loved to have an O2 meter to see what I'd done to that profile.

The fish were not interested. A little lethargic nibbling but no aggression. The next day, feeding was back to normal. Perhaps it was messing with their routine, perhaps they had gone to the far side of the pond with the bottom junk brought up. For whatever reason, normally hungry fish just didn't show up to eat. Snappers didn't mind the extra food. Definitely learned not to mess with the fishes' schedule and environment.