Elastic for waist band?

[Mermaid Tula]

is there any specific types of elastic I should be looking for?

I'm planning on doing both an elastic waist band, and having a zipper up the back.

[Winged Mermaid]

It depends for what kind of tail you're looking for. A wide one will give a more secure fit and uniform look for neoprene or neoprene based tails. For fabric, I'm not sure. What I got and what I have seen used is 1.5-2'' wide. You can buy this type of elastic by the yard (or by the inch if you are specific with the fabric counter person) at fabric stores like JoAnns. Be sure to purchase clasps that can be fastened and unfastened without you seeing and also quickly for your safety. They have a myraid of different clasps and fasteners for you to chose from. I suggest something on the slim side if possible so it will remain hidden better. Also better to put the clasping part where the zipper slit is for a few reasons including hiding it better and accessibility. Hope that helps :)

[Mermaid Tula]

Thanks for the info Iona, my first tail is going to be fabric tail. Thanks for the clasp info too, I would have never thought about that.