Whats this?

[tiffanyniehaus]

we just got some new live rock and we knew some had corals but what is this? I touched it when i was putting the rock in and its mouth seemed to open and it had little tenticals that come from under the side of it. It looks pretty neat but what is it. It obviously moves because it has already moved about an inch from the hole in the rock you can see in the picture.

 

[dogstar]

Maybe Scutus unguis a black limpet.

 

[tiffanyniehaus]

what exactly is that? do they have a special diet?

 

[socal57che]

A limpet is a mollusk with a cone shaped shell. They can attach themselves so securely that you cannot pry them from rocks. They usually suck up tight as a drum when touched. Doesn't look like the limpets I have seen, but it could be.
pics and limpet info at: http://www.gastropods.com/Taxon_pages/Group_Limpet.html

 

[jawfish101]

Does it look like this? If so, it's an Scutus antipodes, or Elephant Slug.