Derasea diagnosis

[Rovert]

Can you all help me figure out what might be wrong w/ my Derasea? I notice a 'crimp' in the mantle, and a bit of tissue recession in a spot or two, and want to be sure I'm not in for trouble. (photos below) Note the area immediately above the incurrent siphon.

Lighting should be ample. It had about 10 days under 4x96w PC flourescents, but I'm now up to 2x250 10K HQI over a 72 bowfront.

I don't see any pyramidellid snails, but that's not to say they're not there, so it still remains a possiblility, but I'm kind of stumped here, and wanted to be sure I caught anything before it went terribly wrong.

TIA!

http://www.webpak.org/images/deraseamantle2.jpg
http://www.webpak.org/images/mantlecl-sm.jpg

[DJREEF]

Is it possible that someone/thing may have run into him, or taken a nip? It looks like the mantle was torn and now is healed back. Pyramid snails aren't going to generate damage like that, even as slight as it is. Check him out tonight, with a flashlight, after the lights go out, you may have a rogue crab in there up to no good. What kind of fish do you have. You might have a rogue fish. Or it could just be sloughing shell as a by product of rapid growth.

DJ