This recipe calls for headless, butterflied, boned rouget. Have your fish monger prepare the fish (but be sure to ask for the heads and bones to make the Garlic Broth recipe below) or do-it-yourself. To prepare the fish at home, begin by cutting off the heads. (Remember to save them). Slice down both sides of the back bones, being careful not to cut through the bellies. Using scissors, snip the bones just inside the tail and remove the entire frame. Use bones from lean white fish like snapper or bass. Bones from dark fleshed and oily fish (mackerel, tuna, salmon) are too strong tasting for fumet.