few cichlids eat snails; however there's a very pretty Tanganyikan that DOES eat them:
Neolamprologus tretocephalus.
Now you might hear all kinds of scary stories about this fish misbehaving very badly with a huge overload on nasty characteristics.....
They're ALL TRUE
if you have a pair!
A single tret will be an asset (they're like a very colorful baby frontosa; all black white and blue), and will rid you off any snails, and it won't be agressive at all, although it can claim one cave and chase off the occasional intruder.
pretty, huh?
"And he piled upon the whale's white hump the sum of all the rage and hate felt by his whole race. If his chest had been a cannon, he would have shot his heart upon it"
Jean-Luc Picard