Please help id this snail

[YellowTang2]

Hello all. I've got these snails pop up in my tank recently and I'm worried that they are the type that like to eat corals? Cos they've been sticking to several "jewel" corals and seems like they are eating one of them up and it's receeded by a quarter off the side so it looks like a cut orange from one side.. And also now I see about 3 more so there are like 6 of these happying "eating" away?

Are they harmful or just eating away what is already dead?

Many Thank...

If they are harmful I'll have to quickly get them out before they migrate to another coral....

[Clownfish]

looks like naussarius snails.... do they bury themselves inside ur sandbed, onli comin out at night? n disappear fast when u switch on ur lights? they hav a long 'tentacle' in the front?

most of their diet wld be detritus as these r scavenges

reference for u:

http://www.liveaquaria.com/product/prod_Di...cfm?pCatId=1133

[YellowTang2]

Actually they don't disappear in the night, actually they are in full view the entire time they are sitting on my jewel coral. Actually when this pic was taken it was on a different coral, 2 days later I see them on the current jewel and have been there since gobbling up what seems to be the coral? I can't be entirely sure that that portion of the coral was dead in the first place, and they are sitting on one portion of the coral that had a ridge. I can't seem them at all so can't tell if they have 1 long tenticle....but I do seem to have about 7 of these.... of different sizes. They aren't the pyramid snails everyone so cautions about are they?

Humm looking at the link you provided, they do seem similar. Maybe they are just eating up the portion of the jewel that is decaying? I'm not entirely sure though...just mine aren't so shiny...