finally someone has the answers to this very special question
"where do you buy mermaid tails" so here are the amazing sites to buy mermaid tails that you can actually swim in.
  1. Ebay.com/mermaid tails  surprisingly eBay does sell alot of good mermaid tails for a low price for good but cheap i recommend fin fun just type fin fun mermaid tails and there you go
  2. MERMAGICA.COM is a another amazing site to got to they are amazing im getting mine from there in a couple of weeks
  3. you can actually rent them from a website called:MERMAIDRENTALS.US they are also amazing
  4. one website is EMILYANGELFISH.COM they are really nice but are pretty expensive but are awesome.