A fish has a heart, which is next to its gills and attached to its neck. Located in the abdominal cavity closest to the pectoral fin. But fish is the lowest, with only two cavities, an atrium and a ventricle, which can squeeze and promote blood circulation. The unique organs of fish include gills, fins, scales and swim bladder, in which gills help them breathe in water, fins provide power and keep balance, scales protect themselves, and swim bladder can float and sink easily.

Fish are mainly divided into freshwater fish and marine fish, but both of them have the characteristics of tender and delicious meat and rich nutrition, and are good sources of some vitamins and minerals. Fish has the effects of strengthening brain, improving intelligence, invigorating spleen, nourishing stomach and lowering blood pressure. Lowering blood pressure: protein is rich in methionine and taurine.