The koi fish in the pond are lining up and spinning in circles? They are just fighting for food...

01 Why do Koi fish line up in long queues?

From a scientific point of view, fish schooling is a common behavioral phenomenon that exists widely among fish societies. Through field expeditions and underwater camera data collection, scientists have found that many fish have the habit of schooling. Fish schooling behavior may be related to their survival strategy, such as increasing their size to intimidate natural enemies and reduce the probability of being preyed on. In addition, when food is scarce, fish may forage alone; when food is sufficient, they are more inclined to school to ensure survival. Even changes in water pressure such as water temperature, water flow or water pressure may affect fish schooling behavior.

Next, let’s talk about the koi carp lining up and circling in Taiyuan Park.

02. How do schools of fish gather together?

When I saw the video, I was really surprised. Later I found the original video and felt that I was really...

I took screenshots of the whole process, which took a total of 39 seconds. First of all, you can see that the fish were very scattered at the beginning.

Especially the group of fish in the lower left corner, it is a very common phenomenon that fish like to gather near water plants. Then there is food in the distance, and the fish begin to form teams to grab the food...

This is a very normal behavior of a school of fish. Looking at the group process, especially the group of fish in the lower left corner, it is obviously an irregular formation. In other words, some are close, some are far, some react quickly, and some are fast. Next, several schools of fish began to merge...

As we all know, fish are relatively low-level creatures, so they tend to follow the herd. As can be seen from the picture, fish do not go directly between two points, as a straight line is the shortest. Instead, they move in a twisted manner.

03 Fish School after Reunion

At this time, the school of fish began to contact the first group of running fish, and then followed them, forming a straight line, which was considered the beginning of convergence.

However, it can still be seen that the lower left corner is not a straight line, but a scattered fusion process.

You can even see that at this time, there is still a group of fish that has not arrived yet, and there is an obvious problem of not being in line and gaps in the middle. Well, finally the formation is formed...

Then they started eating around the food (first come first served and the last ones squeezed in), but there were a few "traitors" among them.

04 Why is it round?

Because they came from a long distance! If the fish had been waiting in one place, this would happen.

But if you come from far away, there must be a first come first served principle.

So the fish that came first were squeezed, and the fish that came later kept coming up, and finally they could only circle. (If it wasn’t a circle, it would be unreasonable. The fish that came first were not full, so they were pushed away by the fish behind them. If they wanted to eat more, they could only circle, otherwise they would all run away.) If they came from all directions, the middle would probably be squeezed. This time, they just came from one direction. Then the fish scattered...

From here, we can see that this is actually a very common process of fish fighting for food. From the angle of shooting, well, no more words...