Shelless snail Should I worry

[cd5]

I have a snail that was a hitchhicker in my tank, it looks exactly like a snail without a shell, Should I be worried,

 

[Civicman86]

might be a slug

 

[MT79]

It's most likely some type of nudibranch. It is very hard to say w/out a pic exactly what it is and if you should remove it. You may be able to get an ID here-
http://www.wetwebmedia.com/nudibran.htm

 

[Fluff]

To me it sounds like Stomatella varia. It actually has half a shell. It's a very good algae grazer and will reproduce easily in your tank. Not harmful at all.

http://www.reefs.org/hhfaq/pages/main_pages/faq_rock2.htm

Check there, nine pictures down.

 

[haus]

I thought I had a slug, but it was a stomatella. Here is my post with a pic of what I had.

http://www.aquariumadvice.com/viewtopic.php?t=55392&highlight=stomatella