There are reports that certain wrasses will eat them, problem is pyramids are nocturnal and wrasses are diurnal. While I have had six line wrasses and canary wrasses pick them off it was not sufficient to really make a significant difference.
Manual removal is really the only means unfortunately.
If you only have snails my recommendation is to remove all snails and go without snails for several months. If you have clams that is a whole different ball game.
There are different types of pyramids, and some say ones that are predators to clams do not bother snails and visa versa, well every time I had pyramids they did not differentiate between snails and clams.
This problem will be a whole lot easier to solve if you do not have clams