They won’t eat fish poop much just dead or soft stuff. They will mostly glaze on the plants. Eating algae and dying soft parts. They will kinda crap over all your white sand though. Worse material visually for them. They kinda poop like rabbits.
If you want them to breed I would suggest taking a single small fish food flake and crushing it in to the tank every couple of day. That will be enough nutrition along with the algae. I only feed when I want numbers to start increasing but my tanks are more gardens than animal habitats.
ziggykitten 
They won’t eat fish poop much just dead or soft stuff. They will mostly glaze on the plants. Eating algae and dying soft parts. They will kinda crap over all your white sand though. Worse material visually for them. They kinda poop like rabbits.
If you want them to breed I would suggest taking a single small fish food flake and crushing it in to the tank every couple of day. That will be enough nutrition along with the algae. I only feed when I want numbers to start increasing but my tanks are more gardens than animal habitats.