I think it looks good. Do you have anything specific about it that you want to hear about? Like something that you had trouble with, or want to improve? Your proportions look pretty good, and I think you're using the medium well. You might want to clean it up a little with a kneaded eraser. That charcoal really smears a lot, doesn't it? Um... what else? I really like the lips. Your eyes are a little big and they look pretty intense like you're trying to say something without words. Over all I think it's pretty good.
Costco's mahi mahi is actually fairly decent and it's a lot cheaper than buying, say, salmon or halibut. I like to marinate it in some sake and soy sauce with a bit of honey, garlic and ginger. Then I broil it with sliced onions. Mmmm... teryaki-y