Not sure about the shark wayne, i know they are scavengers so they possibly will, i've had a few sharks but never in a tank with snails.
dana307, if your tank has been cycled for a while i recommend taking out the filter and leaving it out for a while, float the filter material in the water (so the good bacteria doesn't die). This will allow the clown loach access to "all" the snails, goodluck,
Luca.