Carassidae? Pleuronectidae fish? (I don't know exactly what kind)
The body is very flat, and the adult fish is asymmetrical from left to right, with two eyes on the right side of the head, and the mouth, teeth and lateral fin are asymmetrical. The eyeless side usually has no pigment? . A newborn flounder has the same body shape as a normal fish, with two eyes on both sides of the head and a middle mouth. When the young fish grows up, one eye gradually moves to the top of the head until the other side, and the mouth is gradually distorted until the adult flounder permanently lies on one side of the sea floor.