Now cod are basically frozen slices. Silver cod meat is white, and there is no particularly thick and obvious red line on the meat. The fish scales are very dense, which is the kind that is pressed one by one. The big cross section is real cod, and the small cross section may be oily fish. This is because cod is bigger than oily fish. There will be a yellowish or reddish line in the middle of oily fish, but cod does not.
Cod stewed with tofu, which is common in the market, is probably fake. Cod is a deep-sea fish, rich in unsaturated fatty acids and DHA. The "fake cod" is actually called "oily fish". Its body fat contains a lot of wax, especially for children who eat it. If you find that there is a lot of oil in children's defecation, it is basically a trick. The solution is to buy the whole fish, or go to a large supermarket to buy a fish called "silver cod". Fish is nutritious, high in protein and low in fat, so it is recommended that you eat it regularly.