Our HBG are pretty aggressive towards swimmers. (I should say “floaters). If you are actually swimming and moving around they will seldom hit you, but if you grab a noodle and just float there for a few minutes, they’ll find you. If I wear a t-shirt and get away from the dock, they aren’t nearly as bad.

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