Laryngodon is a characteristic of CYPRINIDAE. During the evolution of hundreds of millions of years, the teeth of the upper and lower jaws degenerated, while the hypopharynx evolved chewing function. Our common herring, grass carp and carp all have this feature.
Goldfish belongs to the same species as crucian carp in taxonomy. Compared with Carassius auratus, the external morphology of goldfish varies greatly, but the whole fish body can be divided into three parts: head, trunk and tail. The front end of the head is the mouth, and the back is the nose, eyes and gill cover. Some species have sarcoma at the top of their heads, some species have villous balls above their noses, some species have prominent eyes, and some species have blisters or blisters, and some species have gill cover leakage to form gill turnover.
The trunk of goldfish is covered with scales, including normal scales, transparent scales and pearl scales. There is a lateral line on its side, and the scales on the lateral line, scales under the lateral line and scales under the lateral line are different for different kinds of goldfish. Typical goldfish have pectoral fins, ventral fins, anal fins, dorsal fins and caudal fins, but some species have no dorsal fins or anal fins. The tail of goldfish is composed of tail handle and tail fin, and the shape of its tail fin is varied.
The function of throat teeth is to cut off or crush food, not to bite people. They are deeply hidden in the throat, which determines that this fish is relatively gentle. Because as a fish, the mouth is its weapon, and now this weapon has lost its offensive ability and has become much weaker.
If you want to get close to the goldfish or koi fish in the courtyard fish pond, you can safely feed it with your hands, and it won't bite you. Some fish friends often play with big koi fish because they know that koi fish is safe.
Goldfish is an ornamental fish domesticated from wild crucian carp. China was the first country to domesticate goldfish. In nature, the body color of crucian carp is gray on the back and white on the abdomen, so it is easier to avoid enemies in natural water. Sometimes, the pigment cells of crucian carp will mutate, making the fish turn golden yellow. Without human intervention, such a mutation will be eaten by the enemy, because it is easy to expose the target. China people began to discover and use this mutation at a very young age.