to be or not to be

I have a few snails in my tank that I believe are detrimental to my reef. They have a shell and a mouth that sticks out like a Nassirus snail. I saw some of these at local pet shops and they take the snails and feed them to the Trigger fish they have. Anyone know what i'm talking about? What are they? How damaging are they? What do they eat?
thanks for shedding a light on these snails!:-/

 

its hard to tell there are so many snails some eat corals, some will go after clams and such ill take a look around and see if theres anything that resembles the nassairous snails. i know nassiours are a great addition to a clean up crew.

 

Could this be what you are referring to??



This is a Whelk, a snail that consumes dead livestock on the reef. It will also attempt to attack and kill snails. These are carnivores. I had at least six of these in my 55g reef for the past year, and never had a problem. After acclimating a baby Golden Maxima clam, the next day I found all the whelks finishing off my beautiful clam. They definitely attacked it - as clams are part of their diet - I only learned later. (sigh) NOT Reef-safe at all. It looks like a Nassarius snail! <-- learn how to tell the difference.

from http://www.melevsreef.com/id/kritter2.html And not from my personal experience