Could be simple timing. Cooler water might account for less activity, especially if you had been catching them during a spawn or prespawn feeding binge. Also, did you harvest those fish or release them? Any chance others are fishing your pond without your knowledge?
Released the fish back. was checking to see what my population was like. No chance anybody else is fishing it.
Also, I did notice as the fall came we had a number of dead fish. Nothing like the entire population but several. Probably a dozen that I could count. Don't see them anymore, but for a couple week stretch we noticed dead fish
