The profundal zone is dimly lit and cold. Mostly heterotrophs are found in this region. Most of the animals, which are called as bottom dwellers that live here are mostly scavengers and predators, for example crustaceans, crabs, fishes like eels and glossogobius, snails, turtles etc. They adapt themselves by feeding on dead animals that settle down. Many kinds of bacteria thrive here that help in decomposing the dead organisms. Mud of the bottom floor, tiny particles of dead and decaying matter of plants and animal bodies make the water very turbid. Hence the bottom dwellers rely mostly on smell and auditory senses rather than vision. Hope this helps you :)