Successfully Breeding the Discus

Group of young discus fish

The Spruce / Thomas R. Reich, PhD

Because Discus Fish (Symphysodon) prefer to choose their own mates, aquarists who hope to breed Discus usually buy several specimens (5-10) at a young age. When two fish are seen to pair off, the other Discus are removed from the aquarium, and you have a mating pair to work with. Do not buy a male and a female online and expect them to breed; you will be disappointed. However, a guaranteed mated breeding couple may be a good idea since a pair of Discus usually mates for life. That said, you are looking at a very expensive proposition, mated pairs can run into the thousands, depending on the strain.

Note: If you are lucky enough to have a local store that deals in many Discus, the owner may let you observe the fish for a while and find a pair in the bunch. If the store allows you to do this, you have found a friend indeed, patronize that store for many years to come.

Distinguishing Males from Females

It is nearly impossible to distinguish male Discus from females. As spawning time approaches, the female’s abdomen becomes slightly enlarged because of the eggs she is carrying. A few days before she lays her eggs, the female develops a short tube, or ovipositor, just in front of her anal fin.

In most respects, Discus Fish spawn like angelfish. The eggs hatch in about 3 or 4 days, during which time the parents guard the eggs, fan them with their fins, and work them over with their mouths, cleaning them of fungus or any foreign objects that may befall them. At first, the tiny, sliver-like fry remain nearly motionless on the spawning site, unless the parents move them to a new location, which they seem to do quite often.

Why Most Attempts at Breeding Have Failed

About 4 days after hatching, the young become free-swimming. It is here that most attempts at Discus breeding failed in the past and here is why. Before we knew how this amazingly unique fish had adapted in nature to raise its young, breeders would remove the parents from the tank, as they would angle fish, to avoid the parents eating the young. However, the fry would not eat and began to die almost as soon as the parents were removed. Many different types of fry food were attempted, but at most 1-6 fry were all that could be saved from batches of up to 200 fry.

Parents Are Necessary to the Development of the Fry

Then, totally by accident, several aquarists made a truly startling discovery. They decided to leave the parents with the newly hatched young, since angle fish occasionally make good parents, and low and behold, not only were Discus, good parents, they are absolutely necessary to the development of the fry. They found that the baby discus eats something from the sides of their parents, as a puppy would from its mother. Further, they found that to remove the Discus parents from the fry, was inevitable to starve and kill the fry.

One of the first to observe baby discus feeding from their parents was Gene Woldsheimer, a gifted aquarist-photographer from California, famous in those days for cover shots on The Aquarium Magazine:

Later studies by scientists showed that there is special food producing cells or glands in the parents’ skins. As the babies reach the free-swimming age, they cling to the side of one parent, feeding while they cling. When one parent grows weary of the babies, it shakes itself, and all the babies are transferred to the side of the other parent.

For several weeks the fry continues receiving nourishment from the parents. Gradually they become less and less dependent upon the parents until finally, they are completely on their own. Baby Discus may be nearly a half-inch long before they become completely independent.

A young Discus bears little resemblance to their parents. For the first months, they are elongated, like most cichlids. But by the time the body of the fish reaches the size of a dime, they are nearly as rounded as the adult.

Technical Data for Breeding Success of Discus

There are many shortcuts to breeding Discus today, and I encourage you to try some of them. I was in a local Orlando store the other day called Sealife Marine and in their front display tank loaded with all kinds of freshwater fish of all sizes and shapes – guess what? There was a pair of Discus tending their eggs right in the middle of it all, with customers walking around the tank and me taking pictures!

The Professional Way

We must first know the natural waters of the Discus to understand the perfect aquarium environment for a breeding pair. In nature, Discus Fish can tolerate only small changes to their environment. Their natural water habitats have extremely low amounts of electrolytes, the total hardness being less than 1 dH.

The high amount of humic acids and tannins mean that there is a low amount of bacteria and fungi. The pH value is about 6, so the water reacts slightly acid. To look after Discus successfully, water must be prepared in the necessary way (reverse osmosis) and also checked at intervals of 2 – 3 weeks; otherwise, the electrolyte content in the aquarium will climb too high.

Apart from the lowering of the water hardness, it is especially necessary to achieve the properties of dystrophic waters by adding humic acids and tannins, either by periodic filtration (through peat) or by adding peat extracts. By these methods, the necessary slightly acidic pH value will be arrived at as well.

Increasing acidity with phosphoric acid is not advisable because of the sensitivity of Discus to that chemical. Moreover, the buffer properties of the extremely soft water are slight, and it will counteract its effect. A tank containing Discus should always be very large so that the specimens have enough room to freely swim and turn around with absolutely no impediments.

The temperature should be constant - but may be kept anywhere from 82F – 86F as long as your heating element is large and steady enough to keep the temperature at one never wavering temperature. To induce breeding, it is suggested to raise the temperature from 82F to 86F, only as a last resort, when dealing with a stubborn pair of Discus.

Large water plants (e.g., Echinodorus) Amazon Sword plants in many varieties are among their favorites, also add leached root stumps which will create the necessary cover and lodging places for the pair to make a home.

To really drill down to nature’s way, let’s take a look at totally natural feeding to stimulate breeding activities. Feed specimens on a varied diet, but do not overfeed, ever. Over feeding fouls the water, something they absolutely cannot tolerate ever.

Use black and white Mosquito larva, small Mayfly larvae and crustaceans of appropriate size (Daphnia, Large Live Brine Shrimp). Discus are adept at gathering live food from the substrate, Discus like washing worms from the bottom; however, do not feed Tubifex or Red Mosquito larvae. These kinds of food animals live in the mud of very polluted waters and therefore contain many pathogens and toxins that Discus are sensitive to.

It is very important to remember that if kept under inadequate conditions, Discus react very quickly: they refuse food, the digestive system becomes disturbed (viscous white feces), and they are attacked by the dreaded “Discus disease” and are also susceptible to “hole in the head” disease.

Although Discus are very peaceful towards other fish, they must be kept exclusively in a species only aquarium if you want them to breed. Only there are they at their best and undisturbed by other fish.

Now maybe you are saying to yourself, “wow that is a lot of work and trouble for one fish” and you would be right. You either fall in love with the Discus, and it is worth all the time and effort, or best to look in awe at the local pet store, thinking “wouldn’t that be great to have at home.”

Summary Recap

The above formula was always necessary with wild caught Discus, but with domestic raised Discus, often it can be much easier to induce spawning in a well-mated pair of Discus. Remember to give them the correct water conditions, and a well-planted aquarium, which is large enough for their needs. Always provide the correct foods from when the Discus you acquire is of a young age.

Rear a group of six youngsters in a permanently set up aquarium and feed them on a wide range of foods, including frozen bloodworm, brine shrimp, etc. Remember; specialized commercial Discus foods are also available in many stores and online today.

As the young Discus approach sexual maturity, your school of Discus will start to separate out into pairs and stake out a territory (most likely one pair will emerge, not several). Leave the best pair in the permanent setup alone, and move the remaining Discus into another aquarium out of sight and out of the way from the preeminent breeding tank.

Spawning usually takes place on a flat vertical surface, but many pairs choose to lay their eggs on a broad leaf plant such as an Amazon Sword. The eggs are fanned for three days before they hatch and the fry is then moved around the aquarium by the mouth of the parents many times for another 4 days. The fry becomes free swimming on the seventh day and feed off the sides of the parents.

Finally remember: it is not necessary, nor is it ever advisable to remove the parents from the permanent breeding tank ever. Discus are great parents, and are not fry eaters nor are they young fish eaters. Eventually, remove the young to separate growing tanks for maximum growth. The breeding pair will breed again when they darn well feel like it, not every 3 weeks like an Angel Fish, no use trying to hurry things up.

Fun Fact

Can you guess the other nickname of the Discus? “The Diva of the Aquarium” a well deserved title indeed.