Help ID. Not sure if algae.

[Alvaro_Spain]

Hi guys.

Can you help me ID this "algae" on the crab shell?. They came in the plug of some zoanthids and now I´ve seen it in other parts. It seems like an algae like chaeto but seems to retract when touched. It is also not any kind of nem pest, cos it sometimes is just one alone like above on the shell.

Thanks! any suggestions appreciated. When I pull and take out where they are it comes back

 

[lapin]

maybe

http://www.reefkeeping.com/issues/2002-02/hcj/feature/

 

[Alvaro_Spain]

Thanks!, they don´t seem like any of them but may be family related. At some time I thought they could be hydroids.