All five flounder species are very similar in appearance but can vary quite dramatically in size. Flounder can vary from 5 to 25 inches in size depending on the species, but all flounder species have a rounded, flattened body shape with a medium-sized flat tail fin.
The colours and markings of the flounder are dependant on the flounder species, although all five flounder species have adapted to life in the sand on the sea floor and they are often coloured to be camouflaged into their silty surroundings.
Flounder are carnivorous and highly predatory animals. The flounder hides on the sand on the sea floor waiting for potential prey, which the flounder ambushes once it has been spotted. Flounder prey on a variety of bottom-dwelling marine species including small fish, shrimp and crabs.