Any ideas what this it?

[Madreefer]

I have one of those as well. Noticed it a few months ago. Has'nt grown or spread and is the size of a dime. I put kalk paste on everything undesireable but for some reason have left it alone. So just tagging along.

[RobertScott]

Thanks everyone, I appreciate the feedback. Is it common for aiptasia sp. to have the hooks and barbs this guy has? My pictures don't really show how the tentacles look, but to the eye it almost looks armored (think the monster that ate Boba Fett). Also, it is open light or dark, and the arms are very active, catching whatever it can and pulling to the center.

[Wingin It]

Originally Posted by RobertScott

the arms are very active, catching whatever it can and pulling to the center.

Lots of our corals and anemones do that. Palys for example...well at least the my big ones are like venus fly traps. Catching food and closing in on it. When feeding my Anemones, they usually do exactly what you're describing.

[Fellow]

Check out the (blurry) pics in my post http://www.canreef.com/vbulletin/showthread.php?t=65331

These only come out when the lights are out. Deep purple stalk and bright green mouth.

Similar in shape to the ones you posted but with fewer arms.