The swordfish

The swordfish has a relatively good reputation. For some friends in inland areas, the name of this fish should have been heard. The swordfish is a fish that "lives in rivers and grows in the sea", so it is more common in coastal areas. Usually this kind of fish basically does not show its head. Only in the middle of April of the lunar calendar every year, a large number of swordfish will migrate from the river, reproduce and then swim back to the sea.

Therefore, it is only during this period that fishing for swordfish is profitable. Because this fish is small and looks like a small steel knife, many people also call it "blade fish" or "small knife fish". Fishermen usually set up barrage nets downstream to catch swordfish. In the early years, this fish was on the market in large quantities. Now, due to overfishing, the number has decreased and the supply exceeds demand.

Some fish bones have more bones and some have fewer bones:

The fish bones have a scientific name in biology, called intermuscular bones, which are distributed in the muscle septa on both sides of the fish vertebrae. Small bones, mainly grown in the bodies of lower teleost fishes. The carp, grass carp, and silver carp we are familiar with all belong to the order Cypriniformes among the lower teleost fishes.

Paleontologists have discovered that with the gradual evolution of fish, the intermuscular bones experienced a process from few to many, then from many to few, and finally disappeared.

For example, the order Anguilloriformes, which appeared earlier, has the most intermuscular bones, while the order Cypriniformes, which appeared slightly later, still has intermuscular bones, but the number is already higher than that of Anguiformes. It has declined, and in the later Siluriformes (such as catfish), the intermuscular bones in the body are close to none.

It can be said that the number of fish bones partly reflects the evolutionary history of fish.