Remember all of those acetate taffeta tentacles stuffed with the contents of two bags of polyfill that I intended to wear on my head? About that... I made the hat. It was a simple semi-oval affair with a thick elastic band. I even attached the tentacles in different widths with the idea that it would look like grotesquely elegant sea creature 'hair'. Unfortunately, it weighed so much, I couldn't stand it. So, I abandoned the hat idea and went instead for a sort of apron affair that clips around the waist. It looks just as grotesquely elegant, but hurts a lot less.
The bodice is an altered version of Truly Victorian's off-the-shoulder 1870s early bustle ballgown bodice. I modified it so it was more natural form. I also shaped the back into two points to it would sort of resemble a fish tail and make a nice outline for the tentacles. The skirt is the straight up TV Fantail. I meant this project from the beginning to be a costume rather than a serious reproduction, so there are more than a few concessions.
For the bodice, I was thinking of a long row of tiny mother of pearl buttons. Possibly some glass pearl beading at the neck line, or maybe some orderless self trim with some dangly bits to further suggest "sea witch". I have yet to put in buttonholes or anything else, and the bodice is unattractively pinned to norma-jean (the dummy) whose dimensions are slightly different than my own corseted dimensions.
The tail is the top half of a tea drop shape inverted. The tentacles in various widths were sewn in between the layers and where the waistband attaches for a cascading effect. The base is reinforced with cotton twill and clips together using flat skirt hooks. This will be much more comfortable than wearing them on my head. Now I just need to figure out some kind of train hitch so the fantail doesn't get in the way while doing the waltz and tango.