Cory seem to eat limpets. I say this because I had a limpet explosion in my tank after removing the cory. Nothing else new in many months.
Assassin snails are prolific breeders. I discovered this when I bought three to kill off a large pond snail problem. Within a month, I had over 100 baby assassins, which is why the Cory got moved. They cleaned up the assassin snail infestation that replaced the pond snail infestation.