Freshwater Discus
The discus is probably unknown to many beginning aquarists owing to its size, cost and temperament. The fact that young discus cost upward of five dollars each gives an idea of how difficult they are to breed. A mated pair may cost over five hundred dollars. Although the acquisition of a mated pair may guarantee spawning, raising the spawn is another story. Many advanced aquarists have spent fortunes on all types of equipment for fancy techniques to help their spawn to survive, but very few have had success, though as more tank-raised discus become available the fish become easier to spawn.
The breeding of the discus is similar to that of the angelfish, but the discus is much more delicate and temperamental than any fish that has been previously mentioned. About the only foods it will take are tubifex worms, whiteworms, beef, brine shrimp, and daphnia, and these only sparingly. Many a discus has been lost because it simply refused to eat.
The main interest of these fish is their scintillating beauty and nearly perfectly circular shape. They display beautiful colors when spawning, which may be quite frequent when they are in a tank by themselves. They range in size up to 6 inches, and a 25-gallon tank should be their minimum requirement. The tank should be densely planted at both ends, leaving the center free for them to display their natural beauty.
If you can afford to purchase a half dozen of these young and raise them to maturity—this is not too great a feat if they start eating right away—they will pair off by mutual attraction when the time is ripe. This is about the only sure way to get a mated pair from them, as sex is practically indistinguishable.
In the past few years the discus has attained a much more popular position than it held in the days when it was first offered to awe-struck hobbyists and commanded astronomical prices. Since then it was discovered that spawning them, while still not an everyday thing, is not the near impossibility it was once considered to be, and every well-stocked hobbyist nowadays is very likely to have a few.
Dr. Leonard P. Schultz, of the Smithsonian Institution in Washington, D.C., has divided the genus Symphysodon into several species and subspecies. At present there are five: Symphysodon aequifasciata aequifasciata, the green discus; Symphysodon aequifasciata axelrodi, the brown discus; Symphysodon aequifasciata haraldi, the blue discus; Symphysodon discus discus, the original red discus or pompadour; and Symphysodon discus willischwartzi, the pineapple discus recently discovered by the author in the Rio Abacaxi, Brazil.
Breeding of the various discus species is exactly the same, and the best method to get a well-mated pair is to keep about a half-dozen growing ones together and let them pick their own mates. They should have a large tank, about 50 gallons or more, and when the two are observed to get chummy and claim a portion of the tank as their property, the time has come to give them a tank of their own. This tank should have soft water, a temperature of about 82° F., and have an acidity that measures pH 6.5. Planting should be heavy, to give the pair some retreats where privacy can be attained. As with angelfish, it is a good procedure to lean a slab of slate against one side of the tank. This is generally where the pair will spawn. Some breeders prefer to give them a large flowerpot with the open top down. Preferences by the fish vary, and a little trial is indicated.
Just like angelfish, the pair will swim close alongside each other, the female laying the eggs and the male fertilizing them. Then they take turns fanning and mouthing the eggs, which hatch after two days. The youngsters become free-swimming two days later, at which time they attach themselves to the sides of one of the parents and "graze" there until the time comes to change to the other parent. This is the big difference in discus breeding: the youngsters usually do not do at all well unless they get this slime as their first food. An acceptable substitute food has been found, and the eggs can now be hatched artificially as angelfish eggs are, eliminating the danger of being eaten, but raising the young is still complicated.
It is a fascinating sight to watch the parents "trading" the youngsters. The one with the youngsters feeding on the sides will wait for the other to swim up, then with a quick motion the youngsters are left behind to find their new feeding spot. In about two weeks the youngsters can be "weaned" to newly hatched brine shrimp, and when they no longer feed on the parents' slime the parents can be moved to their own tank. Frequently they are ready to spawn again by this time.
Discus are very timid fish and are easily frightened. For this reason, they should not have their tank where there are frequent disturbances. Any fish that must be left with its young as discus are would be very likely to become panicky and eat the eggs and young whenever frightened.
