HOW TO MAKE FILLETS OF ROUND FISH
1. How to make round fish fillets, here demonstrated on a Northern pike - a popular sport fishing creature that also tastes nicely. Observe that filleting round fish may differ from one fish to another depending on some special anatomical features. The goal is however to always separate as much flesh as possible from the skeleton. The flesh in round fish is positioned on the both sides of the spine, and the guts are on the belly side. You can invent your own filleting technique that you are comfortable with - as long as you get out the most of the fish flesh without ripping it apart.
2. Insert the knife into the abdomen right between the two fins, and down until you can touch the backbone, but not further. Don't make this first cut to close to the mouth or you might puncture a certain badly tasting organ that will partially spoil your meat.
3. Now, slice the knife all the way down almost to the tail, making sure edge of the knife follows the backbone all the time (otherwise your fillets will be uneven).
4. Lay the fish on the side, and make a cut behind the head (once again, keep your distance from the mouth) and all the way down to the backbone, but don't attempt to cut through it.
5. Then, as the knife blade still rests on the backbone, turn the edge 90 degrees towards the tail and start slicing all the way down to the tail while riding on the backbone. You might hear some small bones being teared apart but that's okay. Now you have one fillet. Repeat the procedure (points 4 and 5) on the other side of the fish, so you get your second fillet.
6. Cut off the fin and its bone from its attachment site.
7. Here's how a pike fillet looks like. You can remove the skin if you wish (some people like to eat it as well) by sliding the knife blade right at where the flesh attach to the skin, and then slicing your way through to the other side of the fillet. Make sure to keep the knife edge at the parallel angle with the table, otherwise you might either cut through the skin or cut too much into the flesh.
8. Pike, and some other fish, are (in)famous for their numerous bones. Some people like to remove them at the same time as they prepare the fillets. I find it much easier to remove them after the fish is cooked. The problem with removal is that as long as the flesh is raw, you will have a hard time pulling all these bones. Although it can be done, it is tedious, and may also destroy the architecture of the fish. The choice is up to you - in a restaurant you will probably have to remove these bones before you serve the fish, or do it while prepping, just so you don't have to be caught in the bone removal process while the customers are waiting. There are some websites out there that show you several techniques to remove the bones. Go ahead and look at them if you are interested. As for now, I'm quite happy with what I see at my table! That's one easy way to fillet a round fish.