What type of fish is this?

Can you tell me what type of fish this is?

• Here's a link to a picture. http://i1128.photobucket.com/albums/m486/bansheila/0105011416a-1.jpg It’s the best I have; he was kind of scared of the camera, so he stayed towards the back of the tank. He is a saltwater fish, about 4.5 inches long, and (when he's not stressed) he has a purplish blotch on the upper part of his body and a dark maroon type color stripe horizontally down the length of his body, and a yellow tail. He also has four very prominent teeth and will eat feeder guppies when offered. He's not overly aggressive. He is housed with a Valentini puffer and they leave each other alone, but I would like to know what type of fish he is. I have not been able to find anything on him in any marine fish books. If anyone can help out, please do. At the very least I would like to know what species he is. Thanks a bunch and good luck!

• Answer:

  Maybe a rainbow fish or a baby parrot fish.