Lighting? What is lighting?

It's only 5:33 but I am so unbelievably tired, still, this is finally finished. I'll start the next illustration tomorrow afternoon when I get home, I really need to work faster. I'm not totally satisfied with this, I think mostly it's the bulk of the mermaid's tail and the green in the water that's bothering me, but I need to put this down now and move onto the next, I don't have the time to be a total perfectionist, and I'm too tired anyway.

I do however really like my shark : )