I hate to be a party pooper because I really love this picture, but I hope you decide credit the original artist's design because I know the artist who made a mermaid exactly like this and even the pose/textures are identical to his. His website is at [link] and the original image can be found @ [link] so yeah please credit him it's only fair. ^_^
Late comment is late, but the idea of a blue mermaid flowing in the water is pretty common. So there is no need to give credit to anyone because the designs while having similarities(blue haired mermaid and that's it), the designs are still very different.