I got this idea from a picture of a mermaid I found online that I wanted to copy. I did the gem nail first with the closest colours I had to the picture and then with the help of my son, picked out nail polish colours that matched the gems the best rather than the picture. I am really happy with the results.
This is the photo I found online and loved the colours involved. It seems you can buy this mermaid tail online here at: Mertailor.com.
I used Avon's Golden Vision, Garden Green, and Lagoon polishes, as well as Essence's Gorgeous Bling Bling. The gems were from a couple of Cheeky collections.