This was crawling up the glass this morning. The arms expanded and contracted and the size was about 1 1/2 inches tip to tip. Any ideas what it could be?
Thanks, Jay
http://www.shockingedison.com/images/worm.jpg

Maybe a hydroid? The Sea Slug Forum - Hydroids (http://www.seaslugforum.net/factsheet.cfm?base=hydroids)

Thanks Carmie. My son (350ZTT on this forum), suggested that it may be a "medussa spaghetti worm." Anyway, now we have two of them, and they seem to bud off by losing a piece of tenacle which stays alive. Pretty cool. I love this hobby.
Jay

Yup, it's a spaghetti worm. Cool critters. I'm trying to grow some in a little tank.

They are pretty cool to look at. I have a few in my reef tank. Are they 100% reef safe??

Yes spaghetti worms are reef safe. The ones I've seen always bury themselves in the sand and then wave their tentacles.

The ONLY issue with them is they can become an irritant by constantly dragging themselves and debris over neighbouring corals.

what about clams in the sand bed?

I think they're buried again. Haven't seen them in a couple days. Or maybe the basket wrasse ate 'em!
Jay