I found a great German brand costume for my daughter, This is from Germany and not the cheap chines one that break or its just too heavy that not even adult can move the fin in the water,This one is light and made very professionally for swimming so easy to swim with. Aslo has a very realistic pattern and fit on the body very well and without any fold. You can find them in mermaidubai.com with free delivery to your home.
I found it good to share and if you are looking for play date for your daughter with her mermaid tail let me know to join with my daughter.