A lot of people ask us about the best way to clean fish, and our normal response is to ask them what they intend to do with them. Depending on your intended recipe, there are three primary ways to clean a fish. First, it's a good idea to think about what a fish looks like inside. You don't have to turn into a Doctor Bob or anything -- a degree in fish biology isn't required to cut wonderful, perfect-every-time fillets. To the contrary, I'm not sure if surgeons are necessarily good at filleting three trout quick, getting them breaded, and on sandwiches just in time for the game.
Gutting and Baking, Head on...
The first is to clean them for baking or grilling in foil. This essentially leaves them whole. You clean out the stomach cavity, remove the gills and surrounding tissue, and scale them. Leaving the head on is a personal choice and also dictated by the recipe. Most large bodied fish can be prepared this way, including grouper, redfish, and (our personal favorite) pompano. So-called "puppy" drum - immature versions of the clownlike giants we find under the Bay bridges are another great candidate for cleaning in this way. Snook don't qualify, by the way - leaving the skin on results in a distinctive soapy taste. Back in the days before someone tried stripping the skin off they were actually called "soapfish."
The next way to clean a fish is to turn it into steaks. Longer, more streamlined fish are better suited for steaking. Local species that are popular candidates for steak recipes are Kingfish, Mackeral, and Cobia (yummm!). Imports include swordfish (don't eat them!!! They're almost all dead!!!!) and wahoo (wonderful).
To steak a fish, clean out the stomach cavity, snip off all the fins (you can leave the tail to use as a handle), and start slicing vertically through the body just behind the gill plate. Keep about three vertebrae in each steak - keeping the steaks at least 4 inches thick to allow for proper cooking - you don't want them to get done too fast or they tend to dry out. Grilling, broiling, or smoking are the best way to prepare steaks. A great recipe for steaks is to mix any of your favorite salad dressings and a few tablespoons of parmesan cheese. Coat the steaks liberally with the mix and grill them close to the burner - fast and hot. We tend to like our fish somewhat rare, and this results in the equivalent of a "Pittsburgh" or "Black and Blue." Raw on the inside, burnt on the outside.
Filleting the meat off the body...
The third way is arguably the most complicated to learn, but unquestionably the most versatile when it comes to using the fish - and that's filleting. A well-done fillet results in totally boneless meat - which can be grilled, fried, cut into chunks, used in stews, you name it. There's nothing in the world like a good Snook or Redfish filet, except perhaps a flounder caught in the beautiful waters near the Skyway.
The concept of filleting a fish is that you're going to essentially "skin" the meat off of the underlying boney structure. This image shows the lines the cuts will take.
Here you see the process taken one step further; the lower image shows the fillets -- like wings on a bird in a top-down image -- separated from the spine.
The filleting process essentially "skins" the meat off the bone. There are two ways to filet a fish - starting at the head or starting at the tail. Personally, I fillet from the tail to the head, but most people I know find it easier to start at the head and work back. That's the way we're going to describe.
We've included a few images with this article, which we hope will assist you in learning how to prepare a good filet. Doing it well is like anything else - it takes practice. Your first attempts are likely to result in a ragged, thin, and ripped piece of meat, with most of the flesh still on the carcass. As you practice, though, you'll get to the point where the only thing left are skin and bones - with a smooth, solid, and intact filet from each side of the fish's body.
Making the Cut...
The first thing to do is make a cut from near the gill down to the backbone. There's a lot of bone and hard cartilage directly over the gills, so you'll have to find the first soft (fleshy) point behind the gill. Holding the fish's head, slice down into this soft spot at a slight angle towards the tail. Look at the anatomy picture - all fish are built roughly the same way.
Slide the knife through this cut until it passes from the head out the other side of the fish, near the pec fins. You need to turn the knife blade so that it's lying flat to the backbone.
Use a slight - very slight - sawing motion to slice the meat from the backbone towards the tail. Make a slight slice, and adjust the knife to make sure it's actually scraping the backbone. Keep adjusting and slicing until you've reached the tail. Don't separate the meat from the tail, though. Leave just enough skin intact to hold it in place. Flip the fish over, keeping the nearly separated filet underneath the body. This provides support for the backbone while you're cutting the second filet. If you remove it too early, the backbone sags to the table and makes the second filet more difficult to remove cleanly. When you've made both cuts, remove the filets from the tail (and hence the body).
At this point, you'll have two, (hopefully) whole and well-manicured filets - with skin on one side.
If you're going to throw the fish carcass into the bay (which is just fine - lot's of things are just dying to munch on those great bones), make sure you poke the eyes to remove the fluid. Otherwise the fish will float to the surface. Also, please break or cut up the carcass into several pieces. If a pelican gets one of these intact bony structures stuck in its pouch, it could very well be seriously injured or kill the hapless bird.
Again, to do a good fillet, you need to revisit and keep in mind how the fish is built, and where the filet comes from. Take a look at the image above and notice the gill plate. From both the top and side views, you'll also see the rib cage. The cage covers the contents of the stomach. It's a good idea not to cut into the stomach while you're filleting. The acids will affect the taste of the meat. Once you're done and have the meat off the bone, you should inspect the stomach to see what the fish was eating before he found your DOA shrimp. We always, always inspect the contents of the fish's stomach. We've found strange and wonderful things there.
In the keys about eight years ago, we caught a beautiful 50lb bull dolphin. When we cleaned him, we found a 5 lb "chicken" dolphin in his stomach. It was so fresh we filleted him too. They were both great.
In most cases, you'll want to remove the skin.
To skin the filets, grab the tail side with your fingernails, and slide the knife between the skin and the meat for about four inches or so. Cut a small slit in this skin (along the long axis, tail to head) and stick your finger in it. It will serve well as a handle for holding the skin while you slice the meat off.
One exception is redfish - try leaving the scales and skin on the fish, and roasting them on the barbeque skin side down. For some reason, the armor-like skin and scales hold moisture in the filet and makes for an incredibly tasty, juicy dinner. Simply sprinkle a little garlic on the meat side before you start, and add a little olive oil or butter (better) when it starts to get hot. Test for doneness - when it's ready it will flake off the skin easily.
One last thing. Don't try this with a dull knife. Sharpen the knife before you start, and keep a steel handy for touching up the blade during the process. The knife will be dull after only two fish, so keep it sharp.
Good luck. We might do a how-to filet video one of these months -- but we're sure you can already find them on uTube. You can learn to do heart surgery on uTube -- we can imagine you can learn to fillet a redfish :)