Discus Fish - Genus Symphysodon

Discus were first introduced in the 1920's and are now regarded as one of the most beautiful of all aquarium fish. 

 PD: All discus have the typical almost circular, discus-shape. They have strong lateral compression and large anal and dorsal fins. The Discus has a steep forehead and a small mouth. The iris of the eye is usually blood-red in color. The body and fin color and pattern varies greatly of the species, habitat, and diet. For instance, the red tones are enhanced when the fish is fed brine shrimp. In the vast Amazon basin, separate populations have developed and originally created the differential of color and markings.

 HABITAT: Discus are found in calm parts of small, blackwater rivers, lakes, and deep pools. They are usually found in small groups around submerged, fallen trees; decaying wood and vegetation; and aquatic grasses. Discus tend to stay in shaded areas during the day. The water is usually very clean with little or no pollutants. Discus are widely distributed throughout the Amazon Basin. The water in the natural habitat of Discus is acidic, around a pH of 6.0-6.5; and is very soft, 0-3 dH. Discus are found in warm water with a temperature of 77-84°F (25-29°C).

In Southeast Asia, Discus are raised in soft to medium hard, alkaline water (3-9 dH, pH 7.0-8.0) with temperatures ranging from 81-91°F (27-33°C).

 TANK: Discus prefer large, roomy, tall tanks of at least 40" (101 cm) long, and 20" (50 cm) high. The water should be clean and relatively bacteria free. The tank should be arranged in dark colors and floating plants should be used to diffuse the light. Discus may remain hidden all day if bright light is used. Driftwood, roots, and heavy vegetation should be used to provide hiding places. Open swimming areas should be created. A good filter for removing wastes is essential in Discus care. Partial regular water changes are recommended to keep the Discus in top health. They are very sensitive to pollutants, especially nitrates and nitrites. Discus do best in peat-filtered water.

WATER: As a general rule, Discus should be kept in water with similar conditions to their natural habitat. However, many Discus are raised in captivity and their range of water conditions is more varied. Most Discus can tolerate water with a pH of 5.0-7.5 and a water hardness of 0-8 dH. The water should be kept warm, 77-86°F (25-30°C).

 SB: Discus are calm, timid fish who like to be kept in small groups of 6-8 fish. There is much debate to whether discus should be kept in community tanks or in species tanks. Since Discus coexist with other fish in nature, they can be kept with other peaceful fish. Discus feel more comfortable if combined with small schooling fish such as characins. When the discus see the characins in the open, they are likely to come out, sensing that they are safe to swim. Adult Discus may eat small fish if not brought up with small fish. Take care when combining Discus with greedy feeders such as Angelfish, and Discus may not be able to compete.

 SC: Catfish (Loricarids, Corydoras ), characins (tetras, hatchetfish, pencilfish), cichlids ( Apistogramma, Uaru ).

 FOOD: Provide a large variety of live, dry, and frozen foods. Try to feed Discus as many nutritional foods as possible such as fortified flake foods, water insects, and brine shrimp. Some Discus are very picky eaters and will only take live foods like Tubifex , bloodworms, mosquito larvae, and beef heart. These foods are not especially healthy and should only be used sparingly. Tubifex worms usually come from polluted waterways and thus must be kept clean or the Discus may develop hole-in-the-head disease. Foods formulated for discus are available.

 SEX: The distinguishing of the male and female is difficult. Adult males may develop a small lump on their foreheads, but this difference is not always reliable. During the spawning season, the shape of the genital papillae serves as the best difference. It is round in female and pointed in males, although this difference is also difficult to detect.

Breeding: The best way to breed Discus is too raise a group of 6-8 fish and watch to see them pair off at about 4" (10 cm). If a pair begins pecking of the glass sides of the tank, it is ready to spawn. Remove this pair into a clean tank with a pH of about 6.5, a water hardness of 1-3 dH, and a warm water temperature of 82-88°F (28-31°C). The pair should be provided with a vertical spawning medium, such as a large plastic tube, a large rock, or a piece of slate. This surface will be carefully cleaned by the pair. The female fans and guards the 100-200 eggs, while the male guards the area. The eggs hatch in 2-3 days and the parents aide the hatching fry by gently nibbling on the egg casings. The fry are then moved by the parents to a different area where they are attached by sticky filaments to this new site. After 4-5 days more, the fry attach themselves to the flanks of the parents. The fry feed on a milky secretion produced by gland cells in the parents skin. After about 10 days the fry should be removed from the parents, or else the may overgraze and damage the parent's skin. They should then be fed on Artemia nauplii. Alternatively, discus larvae can be reared on commercial products if they are removed just after hatching. Regular water changes are essential for the survival of the young. The fry grow quickly and develop the discus-shape in 3-4 months.

In Southeast Asia, Discus are bred in medium hard, alkaline water. Breeders keep young in buckets and perform complete water changes 2-4 times daily.

 R: Two species make up the Discus group, S. discus and S. aequifaciatus . There are two sub-species of the first; S. discus discus and S. discus willischwartzi , and three sub-species of the latter; S. aequifaciatus aequifaciatus , S. aequifaciatus axelrodi , and S. aequifaciatus haraldi . Many crosses have been produced and new selectively bred variations have been developed. Discus are wild-caught in the Amazon basin at night by using strong light to mesmerize the fish. The area is then encircled with netting and slowly drawn closer, with all obstructions such as wood being removed. Species of Discus are now considered endangered in some areas. There are numerous Discus forms which have been developed by selective breeding.

DC: Discus are challenging fish to care for, but are well worth the effort. They must have a variety of foods including live, and are sensitive to disease and poor water conditions.