Why does koi fish like to travel with a group?

Koi fish is a noble large-scale ornamental fish, which has won the reputation of "the king of ornamental fish" with its colorful colors, ever-changing patterns, strong body shape and lively and steady swimming posture.

The ancestor of koi fish is our common edible carp. Carp originated in Persia in Central Asia and was introduced to Japan through China and Korea. Koi fish originated from 20 towns and villages such as Valley Village and Yuma Village near the central area of Niigata Prefecture, and has now become a part of Xiaoqiangu City. Koi fish takes "red and white", "Dazheng Sancai" and "Showa Sancai" as the most representative varieties, commonly known as "Fish Sanjia". Other species of carp, such as Golden Carp, German Carp and Fei Carp, can be called koi fish.

The earliest koi fish in the world is from 1804 to 1829, which means that koi fish has a history of nearly 200 years. At that time, among the edible carp raised in the mountainous area of Niigata Prefecture, Japan, it was found that some of them were mutated into colored carp, which were gradually appreciated by people after being improved into koi fish such as Fei carp, light yellow and Bieguang. By 1830, there was a record of buying and selling koi fish at a high price. German carp is very popular because of its patterns made of coarse scales and bright colors on scalless skin. In fact, the orthodox German carp is mirror carp, that is, there are only two rows of coarse scales on the back and flank, so it has high ornamental value. However, the ornamental value of scalless carp is low. Those who regularly spread large scales between the back scales and the belly scales are called redundant scales, and good ornamental fish should not have such scales. Covered with this kind of irregular scales, it is called armored carp. No matter how beautiful its shape and color are, it has no ornamental value.

There are many varieties in koi fish, and the prices vary greatly. Be sure to consider more than more when buying. The general standards are as follows:

In terms of body shape, the back of the fish should be straight, the fish body should be round and energetic, the fish body should be balanced, the swimming posture should be smooth and correct, the mouth surface should not be skewed, the cheeks should not be sunken, the fins should be symmetrical, and it should not be incomplete.

In terms of color, the most intuitive thing in koi fish is color, which requires that the color must be bright, the edge of the layer should be clear, the color layer should be thick and visually stereoscopic.

In terms of stripes, generally speaking, the more exotic the stripes on koi fish's body, the better. The spots should be evenly distributed on the fish, and the patches should not be too broken. It is best distributed on the back of the fish above the waterline. Except for tricolor, the head should not be covered with eyes, and the abdomen of other species should be pure white.

Koi fish is very ornamental. Every time I come back from hospital surgery, I stand in front of the fish tank and look at them. This is probably the best way for me to relax.