We swim a lot in our pond. My wife won't go in if there's snakes around.. Only one has come by this summer, he didn't stay long.
Factor in the price of fish, and my fondness for frog legs, I will endeavor to keep my pond snake free.

12 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (decreasing), SMB, and HSB (only two have been seen in 5 yrs)
I think that's about all I should put in my little pond.
Otter attack in 2023.