Also, you're very knowledgeable on the zoa species! I recently purchased from Brian of BlueWaterTropicals and he corrected me when I referred my rock of zoa sp. as palys. Looks like there's an interesting history going on here and I'd love to know a bit more if you could share! The majority of this hobby call small zoa sp zoas, everything else that's larger a paly, and everything tiny a micro zoa.
I don't really think I'm THAT knowledgeable on zoas' species!!! LOL!! It's really hard to tell them apart and put the right (scientific) names on them. I would love to know thought! It's gonna be hard to take that one as a compliment, sorry! LOL! There are many others here that would know a lot more about the zoas than I!! 
Yes, I think the majority of the people tend to identify them wrongly and that could be in part because of the cartoon names sometimes followed by the label "paly" or "zoa" on the websites/forums...
We know there is Zoanthus gigantus and that some people call them "palys" and/or PEs. The distinctive marks of the PEs (People Eaters), by many, are their full size, the green mouth and the green marks when the polyps are closed. PEs are Zoanthus gigantus, yes, not "palys".
Actually Zoanthus spp. are called "zoas" by many.
Now, zoanthids, which means Zoanthus spp., Palythoa spp., Protopalythoa spp., etc... are also called" zoas" by many.
So one could say: "All my zoas are doing great!" meaning all the Palythoa spp., Protopalythoa spp. and Zoanthus spp. he/she is keeping. Or meaning all the Zoanthus spp. alone!!! Confusing!!
Episoanthus spp., Parazoanthus spp. and others are rarely found for sale, but they are also "zoas" (zoanthids).
Therefore "zoa" is a nickname for Zoanthus spp. or zoanthids in general.
When people in the hobby say "Palys" they are normally referring to Palythoa spp. or Protopalythoa spp., or something they believe to be Palythoa spp. or Protopalythoa spp. :wildone:
The smaller species of zoanthids are probably all Zoanthus sp., yes.
"For the record, their not "Palys", lol. Some(one) about 7yrs ago gave a fancy name to a polyp and called it "Paly" because they didnt know any better and it snow balled from there. They are actually Zoanthus Gigantus and not a Palythoa. The way you can tell is by the skirt when distiguishing from Paly vs Zoa. Nuclear Greens and Purple Deaths and others similar to them are Protopalythoas..."
I agree with the statement above, generally speaking. I wouldn't agree that the skirt alone could be the ultimate way to distinguish them apart at all times, specially for the beginner hobbyist. I would say that most times the skirts on the Protopalythoa spp. are thiner and shorter than in Zoanthus gigantus, comparing samples from the wild. Some environmental influences, and even in our tanks, can change the way skits look too, so... I still see other characteristics to be more important and mainly easier to teach who doesn't know them apart (mentioned above).
Many could get confused with the cartoon names too and call "nuclear greens" other type of zoanthids, but by the pictures we see online they are most of the time are a green Palythoa sp., perhaps P. grandis IMO...
Being a zoa collector, it would be great if I could at least call them by their proper name.
