See, this is why I need to stop writing wall o texts but I have no idea how else to write. LOL because you all end up making such great comments.

I would say that people like Hannah Frasier are VERY FAMOUS professional mermaids (a level Raina is approaching, obviously, but has not quite achieved as broadly as Hannah has yet), while some of the other mers are simply pro mers who don't get a lot of media coverage.
Agreed and that's how I interpreted it too from his examples. Pro=famous. But even famous is subjective. I'm famous in Canada! lol (but p.s. thanks for the vote of confidence) and I think your actor comparison is right on.

Despite what you do, whether that be parties, modeling, free diving, or lectures, if you're getting paid to do it in some form, you're professional in my mind. Even if it all goes to a charity that's pro. Saying something like, "You have to be a free diver to be a professional mermaid" is kinda like saying "You can only be a heart surgeon to be considered a surgeon." There's different breeds of professional.
That's a great example. It made me think too that even people who don't go all the way still end up being called "a medical professional" or a "legal professional" too.

Also if I haven't said it yet, your sig is great