The tilapia is a mild flavored, white-fleshed fish that is steadily growing in popularity. It is easily farmed, and is often stocked in rural ponds to help control weeds and algae. Some states, such as Florida, have developed a wild tilapia population. If you catch a tilapia, it is important that it be quickly cleaned or filleted and stored in an ice chest or refrigerator until consumed. While you would normally either clean or fillet the fish, these steps will describe how to do both.
Hold the fish down on the cutting board and slice the belly lengthwise from the anal vent forward to the bony plate below the gills. Reach into the opening with your fingers and pull out all the intestines. Scrape the cavity clean, then rinse under running water. If you plan on cooking the fish whole, it is ready to use as is, or you can remove the head if you wish.
Make the first fillet cut right behind the gills on one side of the fish. Cut just behind the bone along the gill opening, at an angle matching the gill opening to maximize the amount of meat in the fillet. Cut straight down into the fish, stopping when you feel the knife hit the main bone.
Cut along the backbone, starting at the top of the previous cut. With your knife laid flat against the top of the spine, slice through the skin all the way to the tail. Then lift the flap of skin, with the meat attached, and begin carefully cutting the meat away from the rib bones. Continue cutting by repeatedly sliding your knife against the ribs, gradually lifting the fillet free.
Remove the skin from the fillet by laying it skin side down on the cutting board. Hold the tip of the tail end down with your fingertips, then slide the point of the knife between the skin and the flesh. Holding the knife perfectly flat on the skin, slide it forward with a back and forth slicing motion to cut the meat away from the skin.
Turn the tilapia over and repeat the previous steps to remove the fillet from the other side.