I have filleted both bass and bluegill this way, works pretty good. You will notice that he didn't keep any of the belly meat, although an electric fillet knife will slide right under the rib bones if you want to keep it. Some people say if the fish get any Mercury from the water, it settles in the belly meat just from gravity. Others like to keep it. I have started cutting it out the same way he does just to be on the safe side. Probably wouldn't be enough to hurt, but that is just me.