Looks great so far, I like the hair. One thing I'd do is make the inside of the collar come down first to the shoulders instead of connecting directly around the neck. Depends if you're trying to keep it really low poly I guess.
I'm sure you're more familiar with the Kisame model than me though, so I'm looking forward to the next update.
EDIT
I'm also thinking the temples of his head might go out too wide, since in the art you can see his headband more, and your headband positioning is correct.