The only thing that will actually "eat"in the sense of completely digest fish excrement are snails and of course bacteria. Snails are great for this, as they eat the large bits breaking them down into much smaller bits that the bacteria can more easily handle.
I never see this "poop" but I do have smallish fish, and with the mixed-shade sand and gravel this is invisible.
My dwarf gouramis are pooping machines......the day after I clean the tank the bottom is covered again lol. It does show up much more on a sandy bottom though.