Flounder are a ‘demersal’ fish, meaning that they live on sand and mud sediments in shallow coastal waters. At least three species of flounder occur in the Derwent estuary, including the Derwent Flounder Taratretis derwentensis, named after this estuary where it was first located. Flounder are a bizarre looking fish, with a laterally compressed body meaning they lay flat on the bottom. Their body shape along with finely spotted skin provide a very effective camouflage, enabling them to hide in sand or mud. Flounders start life as the usual cylindrical shape, but as they mature they flatten, and one eye moves across the head to lie next to the other eye on their top side. Flounder are carnivorous and highly predatory. They hide on the sea floor then ambush their prey when it comes close. Their diet includes a variety of bottom-dwelling animals such as small fish, crustaceans and polycheate worms.