Filleting Technique
Part of Fishing
Filleting removes the boneless meat from a fish in clean slabs. It wastes more flesh than cooking whole, but produces easy-to-eat portions free of bones — important when feeding children, when you need uniform slices for drying or smoking, or when you want to maximize the quality of preserved fish.
When to Fillet vs. Cook Whole
| Situation | Best Approach |
|---|---|
| Immediate eating, small fish | Cook whole (gutted) — less waste |
| Drying or smoking | Fillet — uniform thin slices dry evenly |
| Feeding children or elderly | Fillet — no bone hazard |
| Large fish (over 1 kg / 2 lbs) | Fillet — easier to portion and cook evenly |
| Very small fish (under 15 cm / 6 inches) | Cook whole — not enough meat to fillet efficiently |
| Making fish broth | Cook whole, then pick meat off bones |
What You Need
- A sharp knife. This is non-negotiable. A dull knife tears flesh, wastes meat, and is more dangerous because you apply more pressure. If you don’t have a steel knife, a thin sharp flake of obsidian, flint, or glass works. Sharpen before every filleting session.
- A flat, stable cutting surface. A flat rock, split log, or piece of board.
- Clean water for rinsing.
- A container for the fillets and another for scraps.
The knife should have a thin, flexible blade if possible. Thick, rigid blades waste more meat because they can’t follow the curve of the rib cage.
The Standard Fillet (Round Fish)
This method works on most common fish: trout, bass, perch, catfish, carp, salmon, walleye, and similar round-bodied species.
Step 1. Position the fish. Lay the fish on its side on your cutting surface, head to your non-dominant side (head left if you’re right-handed). The belly faces toward you.
Step 2. First cut — behind the head. Place your knife blade just behind the pectoral fin (the small fin behind the gill cover). Cut diagonally downward toward the head until you feel the spine. Do not cut through the spine — stop when the blade hits bone.
Step 3. Turn the blade. With the knife still against the spine, rotate the blade so it points toward the tail, lying flat along the backbone.
Step 4. Slice toward the tail. Using long, smooth strokes, cut along the spine from head to tail. Let the blade ride on top of the rib bones — you’ll feel a slight bumping as you pass over each vertebra. Keep the blade as close to the spine as possible to maximize meat yield.
Step 5. Pass over the rib cage. When your blade reaches the rib cage (the curved bones protecting the belly cavity), you have two options:
- Cut through the ribs — faster but leaves rib bones in the fillet that must be removed later.
- Cut around the ribs — angle the blade slightly to follow the curve of the ribs, separating meat from bone. This wastes a thin strip of belly meat but produces a bone-free fillet.
Step 6. Complete the cut. Continue slicing toward the tail until the fillet separates completely. You should have one clean slab of meat, skin-side down.
Step 7. Flip and repeat. Turn the fish over and repeat Steps 2–6 on the other side. You now have two fillets and a skeleton (the “rack”).
Removing the Rib Bones
If you cut through the ribs in Step 5, the fillet will have a section of small curved bones on the belly side.
- Lay the fillet skin-side down.
- Feel for the rib bones with your fingertip — they’re in the thicker belly section.
- Slide your knife under the rib bones at a slight angle, keeping the blade flat against the bones.
- Cut along the ribs in one smooth motion to lift them away as a group. A thin strip of belly meat will come off with them — this is normal and unavoidable.
Removing Pin Bones
Many species (trout, salmon, carp, pike) have a row of small bones called pin bones running through the thickest part of the fillet, roughly along the lateral line.
- Run your fingertip along the fillet from head end to tail end. Pin bones feel like tiny sharp bumps.
- If you have pliers, tweezers, or even two flat sticks used as pincers, grip each pin bone and pull it out at a slight angle toward the head end.
- If you have no tool to pull them, make two angled cuts along either side of the pin bone line and remove the narrow strip. This wastes a small amount of meat but eliminates the bones entirely.
For drying and smoking, pin bones are less of a concern — they soften during preservation and are easily avoided when eating.
Skinning the Fillet
Sometimes you want to remove the skin — for example, on catfish (which have tough, inedible skin) or when the skin has a strong “fishy” taste.
- Lay the fillet skin-side down on your cutting surface.
- At the tail end, make a small cut between the flesh and skin — just enough to create a tab of skin you can grip.
- Hold the skin tab firmly (pinch it against the cutting surface with your fingers or use a rough grip like sand on your fingers).
- Angle the knife blade slightly downward against the skin and push the blade forward toward the head end, keeping it flat. The blade should glide between flesh and skin.
- Use a gentle sawing motion if the knife isn’t razor-sharp. The fillet will separate from the skin in one piece.
Tip: Leave the skin on for grilling, smoking, and pan-frying — it holds the fillet together during cooking and crisps up nicely. Remove it only for drying thin strips or when the skin tastes bad.
Filleting Flat Fish
Flat fish (flounder, sole, halibut, turbot) have a different body plan — both eyes on one side, flat profile. They yield four fillets instead of two.
- Lay the fish dark-side up.
- Cut along the center line from head to tail — you’ll feel the spine beneath.
- Starting from the center cut, angle the blade toward the outer edge and slice outward along the rib bones, peeling the fillet away. This gives you one top-left fillet.
- Return to the center line and repeat on the other side for the top-right fillet.
- Flip the fish and repeat for the two bottom fillets.
Flat fish fillets are thin and delicate — handle gently.
Maximizing Yield
In a survival situation, wasted meat is wasted calories. Common mistakes that reduce yield:
- Cutting too far from the spine. Keep the blade flat against the backbone. Every millimeter away from bone is wasted meat. Practice by feel — you should hear and feel the blade scraping bone.
- Stopping the belly cut too early. The belly meat (belly flap) on larger fish is fatty, flavorful, and calorie-dense. Don’t trim it off and throw it away.
- Discarding the collar. The collar is the triangular piece of meat behind the head and above the pectoral fin. On larger fish, it contains some of the richest, most tender flesh. Cut it free and cook it separately.
- Throwing away the rack. The skeleton with head attached still has significant meat. Boil it for broth, or roast it over coals and pick off the remaining flesh.
Realistic yield expectations:
| Fish Size | Approximate Fillet Yield (% of whole weight) |
|---|---|
| Small (under 500g / 1 lb) | 30–35% |
| Medium (500g–2 kg / 1–4 lbs) | 35–45% |
| Large (over 2 kg / 4 lbs) | 40–50% |
The remaining 50–70% is head, bones, skin, and guts — all usable (see Catch Processing).
Improvised Knife Techniques
If your only blade is thick, rigid, or dull, adapt your technique:
- Use a thinner blade for rib work. A sliver of broken glass or a sharpened shell can follow curves better than a thick survival knife.
- Score and peel. Instead of one continuous cut along the spine, make multiple shallow scores and gradually deepen them. Slower but more controlled.
- Cook first, then separate. If your knife is truly inadequate for raw filleting, cook the fish whole (gutted) and then peel the flesh off the bones with fingers or a stick. Cooked meat separates from bone easily.
Preparing Fillets for Preservation
If you’re filleting specifically for drying or smoking:
- Cut fillets into uniform strips — 5 mm (1/4 inch) thick for drying, 10–15 mm (1/2 inch) for smoking.
- Cut with the grain (along the length of the muscle fibers) for strips that hold together on a drying rack.
- Remove all skin for drying (skin traps moisture). Leave skin on for smoking (it holds the piece together).
- Rinse fillets in clean water and pat dry before placing on racks.
See Quick Preservation for smoking and salting methods, or Drying Methods for dehydration techniques.
Key Takeaways
- A sharp knife is essential — sharpen before every session. A dull blade wastes meat and risks injury.
- Standard round fish yield two fillets: cut behind the head, ride the blade along the spine to the tail, and work around the rib cage.
- Remove rib bones and pin bones for clean, bone-free portions — critical when feeding children.
- Save the collar, belly flap, and rack — they contain significant usable meat and broth material.
- For preservation, cut fillets into uniform strips appropriate for your method: thin for drying, thicker for smoking.