What is a Back to Nature background? Back to Nature backgrounds are deceptively realistic three-dimensional landscapes that can be used in aquariums and terrariums. They can partially or completely cover the rear glass wall and transform the aquarium into an exciting, lifelike environment in which the animals can thrive. Back to Nature backgrounds (BTNs) not only look good, they also have practical uses: Most animals feel more secure and can orientate themselves better. In fact, some species do not even display their natural behaviour in „empty“ aquariums. Another clear advantage is that all the technical equipment can be installed out of site behind the Back to Nature. The ideal solution is to install a large biological filter behind the Back to Nature that is effective for several years without having to be cleaned.