Discus head is a plaice, plaice family plaice order fish, also known as the half of the fish, plate fish, partial mouth fish and so on.

Flounder in biological classification belongs to the animal kingdom, chordata, spoke fin fish, flounder under the collective name of the fish, the world has about 11 families ****772 species, with a unique asymmetric structure in the fish, that is, the eyes are only long in the body on one side, it is generally believed that the flounder is from a habit of unilateral rest and basically symmetrical perch-shaped fish evolution.

The flounder is laterally compressed, both eyes are located on one side of the head, the mouth, teeth, even fins are asymmetrical, the eyeless side is usually pigment-free, in fact, the newborn flounder and the normal fish are the same, two eyes are located on both sides of the top of the head and have a centered mouth, but with the growth of juvenile fish, one eye gradually moved to the top of the head up to the other side of the mouth is gradually twisted, the two eyes are on the side of the body in the adult!

Habitat of flounders

Flounders inhabit shallow, sandy bottoms and feed on small fish and shrimp. They are particularly well adapted for benthic life on the seabed. Due to their flattened body. The eyes are the same on the upward-facing side of the body, and the color of this side works well with their surroundings; the downward-facing side of their body is white. The surface of the flounder's body has extremely fine scales. Flounders have only one dorsal fin, which extends from the head almost to the caudal fin. They live mainly in temperate waters and are an economically important fish in temperate seas.

The flounder hatchling, newly hatched from the egg membrane, looks nothing like its parents and is very similar to the common fish. The eyes grow on either side of the head. One on each side, symmetrically placed. They live in the upper layers of the water and often swim near the surface.