What is this ? HELP HELP

[john,jr]

I bought a zenia from the LFS fastened to a clam shell. While aclamating I noticed something that looked very much like a spider. After checking it out it has a tube about 2 1/2 inches stuck to the under side of the shell. I don't have a camera on hand but this is the closest thing I find to it.

I sure hope it isn't a bad thing. It reminds me of a fether duster but it is a solid purple color.

 

[mie]

Look up aiptasia.

 

[mak90]

mie Look up aiptasia.
^^ hmm i dunno how to quote..BUT i agree.
i had 1 in my tank and it soon started popping up EVERYWHERE! i was losing the battle so i eventually had to just take out the rocks and let them dry out

 

[mie]

Pep shrimp ate about two hundred of those little suckers in my tank in about a week.