A very beautiful artwork, which tells a nice story. The girl is very well designed, beautiful clothes, the deep green in the hair and the eyes and the reflecting fish scales on her skin are adding wonderful detail and give her this fairytail-look. Her pose looks nice, but I'm not sure if it fits the topic, it's a bit confusing: Is she just holding the prince instead of pulling him out of the water? There could also be a little more expression on her face, maybe she could even look at the prince instead of looking at the viewer.
The background is beautifully painted, the details on the tree are fantastic and the moth is a nice eyecatcher.
I think you created a wonderful peace. But it has definitely some potenital to make the viewer feeling the story more intensive.