As a child reading TFH and Herbert Axelrod they always said it was best to house your fish in as large a tank as possible. My desire to house my large fish led to me building this tank.
Notice how difficult it is to focus. The rasboro to the right of the discus is out of focus because it is about 2 feet closer to the front glass than the discus. The tank is 4 1/2 feet wide so the discus are about 3 1/2 feet from the front.