Fish are vertebrates. It belongs to the Chordata Subphylum Vertebrata and is generally divided into two groups, one is the cartilaginous fish and the other is the bony fish. Most of these animals live in the water, can breathe with gills, while relying on fins to swim, which can also play a role in maintaining balance. In addition, a few fish can survive on land, but not for a long time.
1. Spindle shape: Spindle shape is the most common shape of fish, also known as the basic type. This body shape is most suitable for swimming, fast in the water, and can migrate long distances. Among the common edible fish, carp and crucian carp are in this shape, and the most ferocious fish in the ocean, shark, is also in this shape.
2. Stick type: The stick type is also called the eel type. As the name implies, it is the same body shape as the eel. Besides the eel, this body shape is mainly the rice field eel and the conger eel. The whole looks like a snake, generally living in the bottom of the water, swimming ability is only as good as the spindle.
3. Side flat: The side flat looks like a sail, its left and right sides are very narrow, but the length and height are almost the same. Fish of this size generally live in the middle and lower layers of water and rarely travel long distances. Common species are pomfret, swallow fish, butterfly fish and so on.
4. Flat: Flat fish can be regarded as the worst swimmers, very slow and inflexible, such as rays, rays and so on. They look flat and can only prey on small animals that live on the bottom of the water.
