A very simple sim I made a long time ago that I am putting up by request. She is blue in the game but since 4 of the pictures were taken in Spring, she looks greenish.
The mermaid mesh is by marvine and can be found
here; it's the blue-gold-green file.
The skin is Pixie Serpent by Enayla and can be found
hereThe hair is from Sunair at The Sims Resource mesh T002
here; if it's not still free you can get it
here.