What features of the structure and life of fish are due to the aquatic image of fish?

Fish are animals leading an aquatic lifestyle, which completely determines their structure of life:
1) the shape of the body in fish is streamlined and usually flattened from the sides, or from above, if the fish leads a near-bottom lifestyle, for example, flounder;
2) parts of the body smoothly pass one into another, which contributes to the smooth flow of water around it;
3) the shape of the front of the head is a wedge, which reduces the resistance of water when moving;
4) the dorsal surface is generally wide and convex;
5) the abdominal surface, on the contrary, is narrow and rather flat;
6) the pectoral and pelvic fins are located at an angle to the body, which helps to swim both up and down;
7) tail fin helps to regulate turns when swimming;
8) the body is covered with special mucus, which reduces friction against water;
9) orient themselves in water streams with the help of the lateral line organ, since the rest of the organs are practically undeveloped.