I'm rather suprised with how much I like this pic, expecially the black side's eye. I'm also planning on drawing this creature again, which is a first for me. It started out as a pen doodle of the right eye, but it kind of escalated into this.
Now this is a nice drawing. The shading is done very well on the entire composition (and, in my opinion, is the best part) and the light and shadows compliment the.....whatever's structure. However, I think the shading on the mouth/nose area is a bit too dark to be convincing. The blue pen outline is a nice addtion that makes the piece stand out more overall, but makes the left side of the paper look pretty lazy. As a matter of fact, the entire left side of the drawing looks like you skimped out as opposed to the right side, but it still looks quite nice. The parts that come out the best are his eye on the right side and the fin/scale things along his neck. Overall it's a very nice piece, good job.