Body laterally compressed, asymmetrical, both eyes on the right side. The mouth is anteriorly positioned, the mandibles more or less prominent, and the margins of the anterior gill cover bones are generally free. The side with eyes is dark brown, the side without eyes white. When swimming, the body swings from side to side, but it looks like the tail is waving up and down as it swims forward.

In flounder, those with eyes on the right side of the body are called flounder, and those on the left are called turbot. Flounders usually hide in the sand, leaving only their eyes out, and are extremely hard to spot as their body color changes with their surroundings.

Extended information:

The flounder larvae, freshly hatched from their egg membranes, look nothing like their parents and are very similar to those of common fish. The eyes grow on either side of the head. One on each side, placed symmetrically. They live in the upper layers of the water and often swim near the surface. After about 20 days or so, the flounder hatchling's form begins to change.

When the flounder hatchling reaches 1 centimeter in length, the eye on one side of the flounder begins to move. It gradually moves to the opposite side through the upper edge of the head and doesn't stop moving until it gets close to the other eye.