to put it simply the fancy colored zoanthids , by and large do not have any toxin , in fact most Palythoa that do have it , have it in small amounts , except for certain kinds , when they excrete it its like literally milky . I have never seen in happen in the home tank system unless provoked by some kind of very harsh mishandling . The hobbiests that have had issue I have heard of did really stupid things like cook the rock with live animals on it ! any Zoa fragger would tell you they would be long dead with the things that get done to these hardy creatures. So unless its MAD ugly and looks like that up there on the left and starts milking up the water , I wouldnt worry or stress. I have had colonies of these for years , us oldschool guys used to be like ahh check out the green "polyps" rip a piece off the rock barehanded and hand them to each other as frag trades, and those were the badboi's , In reality there are very few which have it in any kind of major danger level , and they are not commonly sold to hobbiests now for many years , and they are invasive and not too good of lookers , not cause they left a black widow trail of horror and victims...... Always be diligent