Fan Worm Face, Chiton/Worm Body

[Skoch]

I've had this tank going for about 14 months now and started it with live rock and live sand. I have never seen this guy before today when it appeared on a discarded hermit crab shell. It can retract the fans like a fan worm, but seems to have a longer non-calciferous body that is capable of moving. It is about 15mm long and 3-4mm wide. Any ideas?

 

[HotRocks]

@KJ can probably help!

 

[reef lover]

Your saying the hard looking part moves around??

 

[KJ]

Feather duster (Serpula)

 

[Skoch]

Thanks y'all! I moved the shell and it does appear to be a feather duster. I keep a close eye on the tank and I thought I had seen them all, but I guess not. Which is exactly the reason I love reef tanks so much! Always something new to see. One of my CUC must have pushed the shell around sometime this week and rotated it into a position where I could see it. I moved it to the side of the tank I can best see and I'm going to try and capture a better picture of it out now that we know what it is. In person the feathers are a really beautiful deep purple color, and turning over the shell revealed a much longer tube than I thought.