Why are whelks bad?

[sueandherzoo]

I purchased a used set up which included sand, rocks, water, fish, and snails. I've got all kinds of good stuff in there (worms, stomatellas, feather dusters, etc.) and I've also spotted what I think is a whelk (fairly large - about an inch or more).
From the little I've been able to find it seems I should get rid of him but I'm not sure why. He doesn't seem to bother anybody - he just cruises the live rock, and if he is a "meat eater" isn't that a good thing? Don't I want something in there to pick up the food that doesn't get eaten and any dead stuff that needs cleaning up?
He's actually quite attractive, too -- I'm having a hard time justifying killing him.
Sue

 

[renogaw]

they are carnivores. they will eat just about anything, including fish if they can catch them. corals, clams, etc. look up melev's reef--mark talks about the difference between whelks and nassarious snails and tells all the bad things about whelks.

 

[spanko]

Photo by Marc Levenson
Description quoted from Melev's
"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!"

 

[sueandherzoo]

Next time he's near the front of the tank I'll get a picture of him - I THINK he's a whelk but I don't want to evict him till I'm sure he's bad.
Sue

 

[lmecher]

Very bad if you keep clams, their main diet. I purchased a queen conch which turned out to be a whelk and it ate my maxima clam.