If you didn't learn how to clean a fish at grandpa's knee or in Scouts, chances are you never did. Don't be embarrassed–and don't let it keep you from having fresh trout for dinner. Pack a pocketknife or multitool with a blade at least three inches long, and check out "Fish Feast" for some sizzling recipes.
Rinse the dead fish in stream water, vigorously rubbing its skin with your fingers to remove the natural slime layer. Don't bother removing the scales; once cooked, the skin will slip easily from the flesh.
Small trout (less than 12 inches) are best gutted and cooked whole. Grasp the head with one hand, and then cut open the fish's belly from the vent (anus) to the throat, piercing only the skin and leaving the entrails intact.
Hold the fish belly-up, and make a second cut just below the lower jaw and perpendicular to the backbone. Grasp the entrails at the intersection of the two cuts and remove them by pulling toward the tail. Use your knife to scrape out the bloodline that runs along the backbone.
Large fish (12-plus inches) can be filleted as shown below: (1) Hold the knife parallel to the gill, and slice down to (not through) the backbone. (2) Pivot the blade so it faces the tail and cut along the backbone. Leave the fillet attached to the tail, turn the fish over, and fillet the other side. (3) Cut off the tail and remove any small bones in the fillets.
Where bears are a concern, carry entrails and bones at least a half-mile from camp and bury them in a cat hole. Wash your hands thoroughly and change out of your cooking clothes, which should join food in bear-proof storage. In a bruin-free zone: Play by the LNT book and double-bag fish waste to pack it out.
Keep dead fish fresh by placing them in a lake or stream. For the best taste, cook trout within two hours of catching and killing them.