The FHM are good scavengers.
After I stocked my main pond with BG and FHM and before any predators were added, I went scuba diving a couple times. Didn't matter where I stopped at in the pond, deep or shallow, as long as I was above the thermocline (before I installed aeration) within a few minutes the FHM would find me. After a minute or three laying still on the bottom I could feel them first start pecking and pulling the hairs on my legs. Then they would move to my arms and head (laying on the bottom of the pond). If I stayed there long enough eventually I would see a few in front of my mask but since a diving mask looks like a great big mouth opening, they avoided my face most of the time.
This is without predators. Once you have predators the FHM are going to be forced to whatever refuge they can find and will not be out in open water much. But before predators they will be all over the pond and pick up any fallen feed in short order unless you are just feeding way too much. I could take feed down in a pop bottle, open it and whoosh some feed out and stay still, and it would be a frenzy so violent they would stir the mud on the bottom till I could no longer see them.
I also used my Aqua-view, dropped some feed down and witnessed the same thing. They would swarm it till it got so muddy I could no longer see through the camera.
My limited non-exspert opinion is that fish much prefer to eat feed off the bottom than floating. We only feed floating so we can enjoy watching the fish and to monitor if they clean it up. If a person has a way to monitor intake well enough, my opinion is the fish would prefer the feed to sink slowly.
