My initial thought was a long tentacle/polyp sarcophytons , however, he claims that the entire species is more fluid/soft like an anemone collapsing into a tube structure at night. This description obviously would not be consistent with a sarcophyton. Upon further review, I never really saw a sarcophyton with such dense, long, thin and fluid tentacles. Thus, I posted the pictures here for other experts such as yourself to provide input.
Thanks for your input Kevin. Perhaps my initial thoughts were right and I should not doubt myself on the identification.
Anyone else have any thoughts?