Here's some kind of fish creature I drew in pen and ink, and then tried to color using some old watercolor pencils and watercolor paint. I forgot how much harder it is to color things in the real world :) Its based off of the skull of a Gray Triggerfish that I saw in the really cool book called Skulls: An Exploration of Alan Dudley's Curious Collection. For some reason the skull looked like some kind of pompous, royal fish guy. I might try do a similar drawing of a piranha in the book.
You can flip through the book here. http://www.amazon.com/Skulls-Exploration-Dudleys-Curious-Collection/dp/1579129129