I live off grid in rural Maine and i'm putting in a bunch of artificial gravity feed springs in a few months as well as refurbishing the old shallow well. A bunch of old timers up here are insisting that i should put a freaking trout at the bottom, they insist it helps keep it clean by eating any bugs that fall into it.

I've asked around and apparently this used to be an actual thing. Has anyone here ever heard of this or even witnessed it?