The YP I originally purchased from Rex (Rainman) five years ago were all feed trained. All offspring have remained feed trained. I recently cleaned 8 nice sized YP all caught at the north end of our pond (feeder and sunken cedar trees are all at south end).
It’s only a 1ac pond, but when cleaning the fish, I was surprised to see the Optima BG feed in every one. I didn’t think they traveled around the pond that much.

9 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (going away), SMB, and HSB (only one seen in 5 yrs) Restocked HSB (2020) Have seen one of these.
I think that's about all I should put in my little pond.
Otter attack in 2023