I really love the atmosphere you created for this piece.

First, allow me to state that this piece is far better than I have the ability to create, so kudos to you for your skill and effort. That said, however, the serpent queen does not appear to actually be underwater. Yes, the seaweed, and the fish, and the other details contribute some to fostering the aquatic viewpoint, but her clothing is stationary, as is her 'hair,' and the seaweeds or sea-plants. Some motion would go a long way towards cementing the underwater scene.
Excellent execution of color choice and detail work, and the composition does not feel crowded. Also, and possibly most important in a non-surrealist art piece, what is represented is clearly and 'obviously' represented.
Overall grade B or 81/100.