Does anyone have any idea’s on how to make a mermaid costume, like in The Little Mermaid Broadway Show?

I am attempting to make a costume, extremely similar to, like the mermaids in The Little Mermaid Broadway show. I mainly have no idea how to make the protruding fin, what materials to use, techniques to make it, and especially how to attach it to the rest of the costume. Any help would be much appreciated!!!

Well, the first thing to consider is how to connect the tail to the body- you could use some sort of girdle arrangement around your hips and waist, that you could put the supporting wires on. The skirt can cover the foundations. Look into the Broadway costumes, are there any backstage interviews or videos showing how they work?