Filleting a fish is easy once you get the hang of it, is quicker and less messy than traditional cleaning, and harvests most of the meat of the fish, while providing a virtually boneless, clean fillet (steak).
An electric fillet knife can make filleting much easier, especially if you have a large number of fish to fillet, such as when you catch a haul of bluegill, perch, small bass or trout.
Start by cutting vertically just behind the gills, down to the ribs and backbone. Turn the blade and cut along the spine and ribcage back toward the tail. Be careful not to cut too deeply and through the ribs or into the internal organs. Near the tail, stop and flip the fillet over past the tail, leaving the last little bit connected.
This next part will save you a world of trouble if you do it right. From the tail end, cut through the meat down to, but NOT through, the skin. Hold your knife at approximately a 45 degree angle and basically scrape back and forth to remove the skin from the fillet. If any rib bones are attached to the fillet, you can remove them with your knife without really losing any meat.
Turn the fish over and repeat the process for the other side. Now you have two beautiful boneless, skinless fish fillets. Cook and enjoy!