I love it! Looks like it was painted, but you do these in photoshop right? I wish I knew how to paint digitally. You're work is so incredible! You MUST put out tutorials on how you get the brushes do do that! Maybe one just for me?
as long as you show how your technique works, it'll be spectacular. I figured you used simple brushes, but there is just something I can't figure out about digital painting. I'm hoping your tut can help.
The mouth reminds me of a baleen whale, and the eye of something between a fly and a mouse... fly because it's big and shiny, mouse because it is all black.
The multiple dorsal fin idea is cool, but I would have either done the middle one biggest, or have the first or last biggest and then taper down towards the other direction. Makes it seem more streamlined in my mind.
I don't see why it needs the pelvis-like fin girdle, but I assume that it is very important in your master plan. As always, your fin style rocks the world.