I have a flame cardinal that is very active.
He will eat right from my fingers, but always lets the Maroon Clown eat first. He is a little skittish when you walk up to the tank during the day, but at night he is constantly out and about. They are typically much more active at night. Not the most beautiful fish, but very active and eats about anything. Like it was mentioned before, he has a big appetite.
A very interesting fish, good addition if you want a peaceful fish.
Also good if you want a little movement in your tank after the lights go out.
HTH....MCF