I've always wanted one and still have yet to set up a tank with the equipment I have to house a frogfish. I really got to get around to getting that nano going. Very nice specimen you have there, and doubly nice that it turned from black to yellow. I've heard the same happen, and in all sorts of colors too!
By the way, very cool avatar Looks like a helfrichi firefish to me.
Im in the process right now of trying to get my frog to turn red. Im documenting the process. He is pinkening a little, so I have hope that he'll change. I repalced all his natural decor and added red background, substrate and plants.