What you need for this costume is: hot glue, hot glue gun, fabric glue, sea shells, fish net, black leggings, tulle & sequin fabric (colors of your choice) a bracelet, ripped green fabric or fake seaweed, some thread & body paint (optional)
1st, I cut out some fish net, roughly in the shape of a halter bikini top (use your own for a pattern if needed but it doesn’t need to be exact) The hardest part of this was finding two clam shells the same size to cover up your uhm…ta-ta’s. Lay the clam shells down how u want them (you may need to measure yourself) hot glue the fish net to the inside of clam shells, & glue the green fabric or seaweed inside the shells so pieces are overlapping the edges of the shells.
For the tail, measure the sequin fabric so it fits around u like a skirt, cut out a shape of a long triangle, it should be about a foot longer than your feet when you hold it up to your hips. Use fabric glue to glue just a foot of the small end of the tail together (making a tube shape) cut tulle into a few large triangles for the fan part of the tail & glue to the pointy end.
When the opening of the skirt is on your hip it should create a slit in the skirt, fasten the top with buttons, safety pins, snaps etc. sew the top corner of the fan part of the tail to a bracelet so it will hold the tail up as u walk. you need black leggings under the skirt (assuming its cold on Halloween) glue small shells to the top of the shell top. the top should tie on just like a normal halter bikini top. I carefully painted fish scales on my sides (optional)