Question: To help the toddler make a mermaid tail!
Option 0: Cut shiny mailing envelopes into half circles and glue them onto a long skirt in the childs size. Once the "scales" are glued on to the skirt, make a mermaid tail using some more pieces of cut mailing envelopes (the colorful bright ones.
Option 1: Use enough fabric to wrap around the child and then fall to the ankles. Now take gold or silver fabric paint and create "scales" on the cloth, now glue some tule around the bottom to make it flare out for the mermaid tail.
Answer: 1