Unidentified animal in my tank...help!

[megs1]

(I also submitted this in New To Hobby, but someone suggested I post it here also)

I looked at my tank as soon as my lights came on and I saw this slug like looking think on my glass in the back. It was moving fairly quickly. It got on the bottom of my pre-skimmer and then got onto a rock. I couldn't find it so I decided to take a few things out of my tank to see if I could find it on the rock it crawled onto. It was curled up in a ball in this little hole. I took the rock out, put it in some saltwater and the thing crawled out and I got it into the water. What is it?

This tank has been set up since September and the LR came from the previous owner and some from my 20 gallon SW tank I had set up at the time. The only thing I have put in the tanks are some fish, so I'm assuming this guy has been in there a while. It is currently in a bowl of SW because I am not sure what to do with it. I figured I'd get him out while I could in case he's bad then I wouldn't have to hunt around for him later.

Does anybody know what this is and if it's good or bad? I'm sorry I couln't get a better picture.

Thanks!

 

[Snowreefer]

looks like cat poop =)

Most likely a stomatella. They are harmless and also good algae eaters.

Put him back in. I have about 20 of them they do a great job.

 

[megs1]

Thanks for your help!

 

[Hormigaquatica]

Ive never seen a black Stomatella in a tank. Its tough for me to see it in the pic, but appears more similar to a Scutus snail. Check out the link to see if it looks familiar.
Scutus

 

[SCUBAFREAK]

i have a few stomatella in my tank and they arent black and dont look like that. a better pic would be better.

 

[barbra]

I have a stoamatelle that looks close to that. Although it is actually a chocolate brown color it looks black in poor lighting.

 

[coralnut99]

I vote for a keyhole limpet. If you can get a closer pic, it should have an elongated white pacth on it's back. These are good guys, algae grazers, and will multiply in some cases. Stomatellas aren't usually black like that, and then to stay in the 1/2 inch size range. Then again, you may have discovered a whole new species!