Not feeding koi
We've heard of situations where people don't feed their koi at all, but allow them to just eat the bugs and algae and whatever naturally. This has gone on for about 5 years.
Does anyone else do this? How can you tell if the fish are getting enough to eat in this manner (short of seeing them belly-up on the surface, which I'd rather avoid)?
I've looked through the other posts and haven't found anything about this.