BC-Axeman

Gorgonians, star polyp, Xenia and leather are octocorals. It seems these are tough in that not much injures them except environmental factors. My Gorgo got shaded out by being overgrown by Xenia.
I've heard Zoanthids are the worst with the chemicals. I have never worried about it as I have a bag of charcoal in the sump.
Goniapora don't need sweepers, their whole polyps will reach out far with a very powerful sting. Nothing in my tank could withstand it. Hammer coral is very good at sweeping it's zone clear. I used mine to corral the Xenia until it died in a crash. Now I have put a frogspawn in to fight back against the Rhodactis. It seems to be working. The Rhodis work by slowly nudging other things away and then dividing themselves. They want to carpet the whole tank.
There is so much interaction in these tanks it's amazing. The subtle slow motion violence is pretty intense too.