How about Spiroribidae. Here's a great answer, words right out of my mouth. My cable, computor & tv are down. You should break them off they will spread in the thousands and your rocks and corals will look like porcupines. Vermetids are thicker with two tentacles. http://www.thereeftank.com/forums/f6/small-tubes-on-live-rock-126277.html post#9