are there really any fish that eat other fish feces? i know bacteria breaks it down, but i can't see another fish eating it constantly and thriving from doing so.
don't look into what type of fish will clean up after them. it's a lost cause. instead, look into equipment that will, whether it's powerheads or wavemakers/etc to push the poo towards your filter inflow, or manually netting it out.
i have a bulkhead at the top of my tank on the left side, that gathers up more feces than i could have thought possible. just from the directional flow of my spray bar on the opposite side sends all the feces straight towards it, and the rays moving around, kicking up the sand/etc will help throw it up into the water column to be sucked up. there's very little feces i actually have to net out, and when the time comes for water changes, the sand gets a little once over with the python, but again, very little is picked up.