I made an observation yesterday evening. I noticed my bluegill surfacing. It was the first time I have ever seen it and seems to have stopped this morning. I turned my fountain on immediately.

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It was happening on a little over half of the surface area. It might be a little more sunny on that side.
It was a sunny day in the mid 80s.
No chemicals have been added in weeks.
Water clarity is what you guys say is ideal or close.
Very little rotting vegetation now.
It was 7ish pm.
They had been fed about an hour prior. There was no food on the surface that I saw. It was opposite the feeding area.
Water depth was probably 1' to 10'.
I was stocking forage minnows at the time.
No current algae blooms. Nice normal green hue. What I consider ideal.
Recent showers. Nothing major. Water has risen 6 or 8 inches, I guess. Prior drought here for weeks.
They didn't look distressed. Just a gulp of air and right back down out of sight. Similar to feeding without the splash.
No surfacing on the less sunny side. It was shaded due to the time of day.
Pond is about 5/8 acre.

Any ideas?