i have been asked by many people, and here it is! this is the exact method i used for my tail.
**PLEASE READ COMMENTS BEFORE YOU ASK QUESTIONS!**
I did forget to mention the Spray Silicone in the first picture, which is $9 on Amazon.com. It is used for divers, and should be applied to the finished tail to prevent stickiness!
This tutorial was a collaboration from many of the mer community on Mer.Yuku.com
Do not swim in a mermaid tail without supervision - This particular tail-tutorial makes a tail that is easily 40-50bls when finished. It will be weightless in the water, but will double in weight after being wet on land.
I suggest practice swimming with a monofin while in the process of making your tail - it will help you learn how to move with the fin and build the necessary muscles to swim with it.
IF YOU ARE INTERESTED IN COMMISSIONING A TAIL:
read this first: [link]