This entry is easily the best I've seen in this entire competition to date.
The proportions are on point, the shading is on point, and best of all, there's a beautiful contrast up the front that sets Ariel apart. That is easily the most striking part of the piece, the bit that draws me in. Don't get me wrong, everything else looks accomplished too -- but you've really got a hook in this piece, pardon the pun. (get it, hook, trident...?)
Just a stylistic choice I guess, one that doesn't make me want to dock points but I just feel... Flounder looks awfully like Flotsam and Jetsam. I'm not really a fan of that. That being said, just how Ariel looks after having taken Triton's place is imaginative. I don't know if for good, or for evil; I wouldn't be able to tell by her garb, her pose and her seeming enjoyment for all things scaly and bat-winged.
Anyway, props to you. Well done!