Dwarf cichlids can eat snails and my snails were all over the tank before the corydoras went in and now are hiding. I caught a corydoras red handed with a snail in his mouth.
Plants grow, leaves die, snails and other herbivores eat the dead leaves, detritivores consume snail poop and make mulm, mulm feeds the plants. Circle of life.
Herbivore poop is large, carnivore poop small because of the amount of food the animal needs to eat to survive. Meats are much more nutrient dense than plants. Think how much material those snails are taking in to have that much waste, they must be doing a great job finding and eating debris in the tank.