Id Please!

[Deedily]

Hello there;
I was instructed from the New member forum thing to post this here. I cannot find out what it would be. I also lost track of him. But....Last night in my tank, after about a month of watching this stringy, clear "arm" stick out of below my rock, I decided to flip it over and check it out. What I found was a system (well, more like a Y) of my sand, glued together into like a tunnel. I tore it open. (this might've been a bad idea.) At the end of one of the tunnels, I found this guy. His body was halfway through the tunnel at the time. He has the body of a shrimp, but the long green mermaid-like tail, and a tongue-like thing that he protrudes, similar to a noodle but its clear. (On later inspection, theres two of them) I outlined the tongue thing in pink.

 

[KeMo]

Like I said on the other page. It looks like a feather duster without its partchmen tube it lives in. + you saying it had a mermaid tail. Also those long things look like the two tubes it has that it slides food down.
It looks just like my feather duster when its not in its tube.

 

[BEASTIEPENDENT]

Perfectly harmless, it's this: http://www.reeflex.net/tiere/2280_Phyllochaetopterus_sp..htm With its two slimy tentacles it searches for detritus.