The difference between these two foods is as follows:

1. Part: Salmon belly is the meat close to the belly of the salmon, while salmon fillet is the muscles from both sides of the back to the abdomen.

2. Fat content: The fat content of salmon belly is relatively high because it is located in the belly of the fish and is also the fattest part of the fish. The unsaturated fat content of salmon fillet is lower than that of salmon belly, which means that salmon fillet has less fat content.

3. Taste: The texture of salmon belly is thicker and denser, and the taste is more delicious. The salmon fillet has fine lines and a more delicate taste.

4. Nutritional value: The meat of salmon belly is fatter and more tender, suitable for people who like a fat and tender taste. The meat of salmon fillet is relatively firm, which is suitable for people who like a delicate taste.