As the name implies, the body of this fish is disc shaped with full dorsal and anal fins reaching to the tail. The body can reach to 8 to 10 inches in diameter. In the wild, Discus are found in very soft, acidic (ph< 7.0) water and prefer to live among the submerged roots. In the home aquarium you need to provide plenty of cover. Juvenile Discus can tolerate large schools while the adults may start to pair off and defend territories. Discus are rather intolerant of poor water quality, so regular partial water changes must be made and proper filtration maintained at all times. When under stress, most Discus will turn very dark and may clamp their fins and refuse to eat.