There isn't any fish I'm aware of that will readily consume fish poop, even most kinds of catfish. You might be able to get something like a weather loach to be attracted to fresh poop but I doubt they would consume it to any benefit, especially if you feed the other fish any kind of food they can go after themselves.
That being said, my ghost shrimp fought over a peace of fish poop like it was the last piece of food on the planet. Just make sure the tank isn't too overcrowded with A LOT of poop laying around and you don't grossly overfeed so the shrimp are waiting on the next blessing from the flake food gods so they get lazy and don't look for anything (dont know if thats possible though, esp at higher temps).
I had mine in with livebearers too and the fish couldn't have ignored them more. Just don't put them in with anything large enough to swallow them just in case.....or anything mean like barbs. Those WILL devour them first thing, trust me I know.
What's funny is you could watch them get a piece of poop, eat off a piece, watch it go into their stomach and see it churn back and forth. THAT is what made my mom decide to never eat another shrimp.....and she hasn't! lol