*glass anenome* heres a link to my journal which has the picture on the last post, if any1 could help me i.d it id be most grateful.
http/www.fishforum...st-marine-tank/
Aiptasia anemone. Can reach plague proportions, though mine never achieve this. I'll have the odd one here and there. Yours has found a hole. If you want to kill it, best route in that case is to just simply cover the hole with a coral expoxy, very Cask of Amontillado.
Others take soldering irons to them, joe's juice, Aiptasia X, lemon juice, hot and/or cold blasts of water, removal of rock, etc...
Generally consider a pest anemone, non-photosynthetic, and very hardy.