1. First, fold the paper diagonally twice.

2. Then fold it in half along the center line and fold it into a square according to the crease.

3. The edges of both sides are aligned to the middle, and folded into a diamond shape according to the crease after opening.

4. Fold the middle two corners outward, and then fold inward according to the crease.

5. Fold the corner at the bottom to the middle, and then fold the corners at both sides inward.

6. Fold the whole origami in half, with one corner facing up, and make it into the shape of a fin.

7. The tail is folded outward and folded into a parallelogram according to the crease.

8. Fold the triangular area twice to fold the shape of the tail.

9. The top fin is turned back to make it more stereoscopic.

10. The two shark fins on the lower side are folded inward.

1 1, such a shark is ready.

Most of the small sharks bought in the market are freshwater ornamental sharks, that is, Su's round belly sharks. Although it is called little shark, it has nothing to do with sharks.

The scientific name of freshwater shark is Su's ampulla. They mainly live in fresh water and like to move at the bottom of aquatic plants. Freshwater sharks can accept hypoxia, and when the dissolved oxygen in water is low, it will not affect their normal growth.

However, they have high temperature requirements. They like warm environment, but have poor adaptability to low temperature. Their favorite water temperature is between 26-32℃. When the water temperature is lower than 18℃, their activity and appetite will be reduced, and they are easy to get sick.