Originally Posted by Dav3
I have the same thing. Only out when lights are off. No one could positively ID. Aiptasia is only response I got.
From my searches online the closest I could get is stripped bead anemone. And there is little info on those. Certainly doesn't behave like any aiptasia I'm aware of.
Dav3, this article on tube anemones might be of some interest: On the Captive Biology of Tube Anemones â€” Advanced Aquarist | Aquarist Magazine and Blog
Looks like our critter may be similar to the banded tube anemone pictured in the article. Lucikly, the article suggests that the stings of tube anemones are not as potent as many think, and may even be weaker than those of aiptasia.
Here are some other relevant portions of the article:
"Tube anemones are distinguished by having two distinct whorls of tentacles. Each whorl consists of a different type of tentacle."
"As adults, cerianthids dwell in a long, soft tube. The tube is constructed from specialized cnidae threads (or, ptychocysts) and mucus, though it may incorporate other materials such as sand. The outside texture of the tube is much like slimy, wet shreds of paper; the inside texture is rather slick and smooth. The tube is typically buried in mud, sand or gravel, though it may be wedged into or between rocks. It may be much greater in length than the anemone itself (>2.0 m long). The tentacular crown emerges from the distal end of the tube; however, if it is threatened, the animal can very quickly retreat beneath the substrate into the bottom of the tube."
Let me know if you or anyone else have any thoughts!