Discus Fish Breeding [Parts 1 & 2]

Part 1


The art of keeping discus fish is both challenging and equally as rewarding. Discus fish are best off when kept in groups of at least six fish. Because of this, it is inevitable that eventually, when the fish are sexually mature, your discus are going to want to pass on their genes to a new generation of baby discus fish. Breeding discus fish is an art in and of itself so learning the mechanics and conditions that will promote this process will allow you to not only successfully raise your own stock of discus fish, but also be able to selectively breed certain strains.


Determining the sex of your discus fish is nearly impossible anatomically until your fish are sexually mature. and ready to breed. Generally, the male will be slightly more aggressive with slightly thicker lips and a thicker forehead. In the wild, these serve as battle armor to protect his female mate and fend off any intruders and other male discus fish. The dorsal fin of the male is also slightly more pointed than that of the female’s, which is more rounded in shape. In juvenile discus fish, however, the dorsal fin of both sexes is rounded, so this method is only reliable for sexing mature discus fish. Some discus keepers argue that the male partner will take on a less intense coloration, with more patterns than his female counterpart. This method of discus sexing is highly outdated, however, as many factors such as diet, stress, and water quality can all affect the coloration of your discus fish.


Another way to sex your discus fish is to compare the size of their breeding tubes, which is a small tube shaped reproductive structure located between the anal fin and the anus of your discus fish. In females, the breeding tube is broader and more rounded in shape, usually with a relatively blunt tip. In males, however, the breeding tube is much smaller and has a more pointed tip. This method is much more reliable, however this difference is only noticeable when the fish are actually ready to spawn, so it must be monitored closely.


There are also behavioral queues that you can look for when trying to determine the sex of your discus fish. Generally, if the female is more shy, the male will often times have a tendency to place himself between the observer (you) and the female fish. There is no doubt that sexing your discus fish is an overall difficult process. Arguably, the most sure-fire way to accurately determine the sex of your discus is to raise a large group discus fish with between six and eight individuals, and then allow them to pair off when they are ready to spawn. By closely monitoring their behavior, and paying attention to slight anatomical differences (sexual dimorphism), you will be able to correctly determine the sex of your discus fish.


Once your discus fish have paired off and selected their respective mates, the process of spawning can finally commence. Now that they are ready to spawn, you may notice your discus fish acting slightly more territorial than before. Often times, the breeding pair will select an area in their tank as their new spawning ground, and will relentlessly defend that area against all that trespass. You may also notice your discus fish partaking in what many call the “Discus Dance.” The male and female breeding pair will approach each other, bow, swim vertically upwards, and then circle back around and repeat the same process. This courtship dance serves as a way for the pair to officially begin the process of spawning, and brings the pair closer together in preparation to raise their young.


Anatomically, visual queues will also be visible that will indicate that spawning is right around the corner. The fins of your discus fish will begin to darken, and the center of their body will become a noticeably darker shade. At this time, the discus couple will select a vertical surface to the lay eggs. The most common method of this is for the keeper to purchase a breeding cone, which is a conical structure made of natural stoneware that provides a substrate for the discus to lay their eggs on. While not required for breeding, it is a good idea to use a breeding cone if your tank lacks other objects such as plants and decorations that would serve as the substrate. In a pinch, discus fish have also been known to lay their eggs directly on the vertical glass wall of the tank.


Until the eggs are laid, the pair will intently clean the surface that they selected as the substrate. The females will position their breeding tube against the surface and lay up to 400 tiny eggs. Larger females will lay more eggs, and smaller females will lay less. Once the eggs are securely fastened to the substrate surface, her male counterpart will immediately come in from behind her and fertilize the batch of eggs.


Once the eggs have been laid and fertilized, the parents must work diligently to ensure the survival of their offspring in this fragile stage of life. Often, the parents will take turns fanning the eggs with their fins to promote circulation. They will also be very defensive of their newly laid brood, and will guard the batch of eggs intensely. This is a crucial time period for the survival of the eggs, so stress and disturbances should be kept at a minimum. If the parents become too stressed, they will ultimately end up eating the eggs, so water temperature, hardness, and pH need to be monitored as closely as possible.


If the eggs are viable, a small, dark embryo will become visible within the first 24 hours. If the eggs are not viable, however, they will take on a pale white coloration. Granted that everything goes as planned, and there are no outside complications, the eggs that do survive will begin to hatch within approximately 60 hours of being laid. As the eggs begin to hatch, and the small fry begin to wiggle free from their egg cases and swim about, the parents will take turns scooping their young into their mouths and transporting them back to the spawning. They will constantly move and relocate the young discus to safe spots as a means of protection until the fry are able to safely swim and explore on their own.


The free-swimming fry can now begin feeding on the slime secreted by both parents, who take turns feeding their young. Known as “discus milk”, this nutrient rich secretion of slime will allow the fry to grow rapidly. In as little as seven days of feeding from their parents, the young discus will be ready to begin feeding on small pieces of real food such as newly hatched brine shrimp.


Part 2


When the process is complete, and you can see your tiny, discus fry begin to grow and mature into the vibrant adults that they will eventually become, you will know that you have successfully bred a new generation of discus fish in your tank. Unfortunately, the process of breeding is completely dependent upon the individual natures of your discus fish, and you may notice that no matter how close a male and female seem to be, they just won’t initiate the process of spawning. This can be disheartening for some discus keepers, as they may think that their fish just aren’t compatible enough. Luckily there are some things that you can do as a keeper to initiate the process of breeding and further raise the chances of your discus fish producing young of their own.


Whether it be breeding, feeding, or simply overall health, there is one factor that seems to be governing the successfulness of your discus tank; water quality. Discus fish are best off in soft water that contains very few minerals, water this is slightly acidic with a pH slightly less than 7, and water that is as clean as it can be. One way to initiate breeding in your discus fish is to perform a 25% water change, however the newly added water should be a few degrees less than the original temperature. In the Amazon, the onset of the rainy season serves a cue for discus fish to begin spawning. Heavy rains cause the rivers and tributaries to ultimately rise in water level, as well as drop in temperature by a few degrees. My mimicking this process in your tank, it may act as a signal to your discus fish to begin spawning. It should be noted, however, that if you are to choose to use this method to initiate spawning, that the hardness and pH of the newly added water should not change. Essentially, the only variable that should change during this water replacement is temperature.


Another way to initiate breeding in your discus fish is to separate the male and female pair. Using either a totally different tank, or a tank divider, you can separate the pair from each other, ensuring no contact is made between the two fish. During this time, the female should be readily fed. Often, a diet rich in bloodworms can be supplemented with the regular diet to promote breeding in females. Once the pair has been separated for a few days, they can then be reintroduced. During this process, the male should be observed closely over the next 24 hours to ensure that he doesn’t show any signs of aggression towards the female. If all goes well, the pair should begin the process of spawning over the next few days.


As mentioned in the previous article (Discus Fish Breeding Part 1), your discus fish must first pair off before the process of breeding can even begin. When you notice that two discus fish have taken a particular liking towards each other, and have confirmed that they are a male- female pair, the newly established pair should be removed from the regular tank with all of the other discus fish to a separate tank on their own, usually between 20 and 30 gallons in size. When the eggs are laid the, the pair is kept with their fry for as long as possible. The fry will consume their parents’ “discus milk” for 7 days before they can be fed normal food, however the discus will continue to consume the milk, in addition to their regular diet, up until around three to four weeks in age. At this point, the baby discus fish are similar in size to that of athumbnail, with mouths to match their new-found size. At this time, the parents will no longer willingly allow the young fish to continue consuming the milk, as the young will actually inflict pain on their parents with the constant pecking of the mucus. It is now a good time and idea to separate the young discus fish from their parents, and place them in a new tank of their own. This is the point where serious consideration needs to be taken, as the parameters and quality of the water of this new tank will ultimately affect how healthy your young discus fish will grow
up to be.


The mucus secreted by the parents provided the young fry with a good portion of immunological benefits, however disease is the number one killer of young discus fish. Commonly referred to as the “four-week syndrome”, this dying off of the young discus fish can be prevented by treating the water. The water that you move your young discus fish in to should be treated readily in order to prevent gill flukes, bacterial infections, etc. Aquaflavin and
Wormer Plus are two popular treatments that many discus keepers choose to add to their young discus tanks.


As the young discus continue to grow and mature, it is now up to the keeper on the steps that are to be taken next. As a discus breeder, it is your responsibility to ensure the passing on of genes from parents to offspring. In today’s day and age, mass discus fish breeders view their breeding stock as simple money makers, and little compassion is shown towards the fish. For many, the more quickly a fish can be grown from fry to sub adult capable of making a profit, the
better. As in nature, not every single offspring is designed to survive to adulthood and pass on their genes. What often occurs is that mass breeders will produce as many fish as possible, grow them as quickly as possible, and then sell them to discus fish keepers, paying little or no attention to diseases, deformities, or ailments possessed by the fish they are selling. The buyer then, unknowingly, breeds a deformed discus fish in their home aquarium, and essentially passes on diseased genes that, in the wild, would never have been passed on. Today, we see discus fish that are bred for their coloration and nothing else. The process of natural selection weeds out the weak, while the strong survive. In an effort to breed the most colorful discus fish, little consideration is taken with regards to brooding behavior (spawning effectiveness) and immunological integrity.


Fortunately, on the other hand, you as a discus fish keeper and breeder have the power to essentially breed the most physiologically fit organisms possible. Through selective breeding, patience, and attention to detail, you can breed your own discus fish that is both visually appealing and extremely healthy. For example, you may notice that when the fry emerge from the eggs, many, but not all, of them begin to die off due to disease. At a time when infection pressure was high, some fry managed to survive. These fry therefore have a much greater capacity to fend of disease and contain genes that are favorable to future generations. Of the fry that survived the onslaught of disease, some grow into very colorful adults, while some may take on a more dull coloration. By breeding these colorful fish with the heightened immune system, you increase the possibility of producing offspring that contain the same traits, and so


Mastering the art of discus fish breeding is a process that takes countless amounts of time, energy, and in some cases, money. Heavy consideration should be taken before you, as a keeper, can commit to regularly breeding your discus fish. Once you have perfected this delicate process, the possibilities are endless, and you can get creative with which discus you want to breed through selective breeding and selecting the traits that you personally find
favorable. In a time when the natural habitat of these discus fish is under constant threat, the future of discus fish breeding may ultimately lie in the hands of future discus breeders to produce organisms that are able to withstand the onslaught brought on by man’s threat to the integrity of the natural habitat of these fish.