This IS the best mermaid image I've seen! It is very realistic and 'believable'! I tried to do a mermaid from stock and the hardest part was the blending between skin and scales. I used a gradient on a mask right about where the scales blend in to the body. It turned out pretty nice, tho, nothing like this!
I love your ideas and your art! Thank you for time well-spent enjoying what you've done!