Observation diary

Friday, May 4, 2019, the weather is fine.

My family has raised seven koi oysters. Some are big red, like a little sun swimming; some are orange, like a big orange; others are colors, like a chameleon. The shape of the small fish is streamlined and the body length is between 6 and 12 cm. I also fed them fish food and flower rolls, they seem to love the end of the flower. When they breathe and eat, the mouth is like a small horn, and the suction is used to feed the food into the mouth.

Wednesday, May 2, 2019, the weather is sunny and cloudy.

Fish is very fond of playing! They sometimes squirt upwards, sometimes downwards, and sometimes chasing me in the water. However, these are all fishes swimming, can they not "go backwards"? By observation, my answer is yes. Do not believe, look at the Koi of my family. When the little guy swims forward, the belly fins are drawn backwards, and the body and tail are swung left and right, creating a vortex flow that pushes the fish forward. So sometimes they can slide through the water for a while. While swimming backwards, the belly fins move forward, creating a driving force like our boating, and the tail swings only to the right or left, and the fish naturally “reverses”.

Sixth grade: 446507460 (Zhang Yuqin)