Why the skin of fish is oily?

The skin of fish is oily primarily due to the presence of natural oils, such as omega-3 fatty acids, which are produced by the fish's body to maintain buoyancy and insulation. These oils also play a crucial role in protecting the skin from pathogens and environmental factors. Additionally, the oily layer helps to keep the fish moist and enhances its flavor when cooked. This oily composition varies among different species of fish, depending on their habitat and diet.