Successfully breeding discus is the crowning achievement of the freshwater aquarium hobby. Discus are easily one of the most beautiful of all the ornamental fish, but have a history of being one of the toughest to keep happy in the home aquarium. Keeping them happy enough to breed is another challenge in onto itself. With the advent of more and more experienced hobbyist willing to share their tips and tricks and the influx of more captive bred generations of discus hitting the market, what once once a seemingly impossible task is more attainable than ever. Here is a step by step guide to breeding discus.
The first step in successfully breeding discus is identifying a male and female pair. Discus form partner bonds when a male and female reach sexual maturity. This makes it more difficult to introduce random males and females together and expecting them to spawn. A far easier trick is to raise 5 to 6 juvenile discus together and wait for the males and females to naturally pair off. To the untrained eye, it can be difficult to tell the difference between the two sexes. Some conventional cichlid sexual dimorphisms apply to discus. A female’s ovipositor will start to protrude prior to egg laying. Males will develop thicker lips and enlarged foreheads. Males will also develop pointed tips to their dorsal fins while females will remain rounded. When you think you have a pair, it is time to move them to a breeding tank.
It is best to breed discus in a 20-30 gallon tank. The main reason for this will become apparent after the eggs hatch, but more on that later. Another reason is that the parents will really get to know each other in these close quarters (Think of it as a conjugal trailer). You will want to move your adult pair into a bare bottom glass aquarium adorned with an appropriately sized heater, sponge filter, and a ceramic breeder cone. You want the bare bottom tank, because you are going to be doing daily water changes and this will help you see all the detritus that needs removal. The heater should be set to a slightly warmer 86-88*F. This will stimulate the parents to spawn, but will also help the eggs develop faster. The breeding cone will be used as a spawning surface.
Water quality will be one of the most important factors in convincing your discus to spawn. To successfully spawn, discus need an abundant supply of fresh, warm, and soft water. Like previously mentioned you will want to increase the temperature to 86-88*F. The conductivity of the water will need to be somewhere below 200uS. Naturally, this will result in a low pH anywhere between 5.5-6.5 that is very poorly buffered. Since the water contains little buffering capacity, you need to make sure that you performing daily water changes of at least 50%. The water you perform the water changes with can be slightly cooler than the breeding tank (around 82-84*F). This influx of cool(er) fresh water can also be a trigger for spawning. To get a constant supply of low conductivity water, you may need to invest in a reverse osmosis unit and mix it with some tap water.
Feeding your discus a varied diet of frozen and dry food during this time will also help get them ready to spawn. Discus are carnivorous, so feeding them a steady supply of frozen beef heart, artemia, and blood worms will be crucial during this energy intensive phase. A variety of flake foods will help balance their diet and prevent nutrient deficiencies.
When the discus are getting ready to spawn they will do this fascinating behavior where they will select an appropriate spawning site and thoroughly clean it by removing any dirt or algae with their mouths. The preferable spawning site for discus is typically a vertical surface like a broadleaf, tree root, standpipe, heater, glass wall, or in this case, a breeding cone. After the parents have cleaned the spawning site, the male and female will begin doing a courtship dance. This dance is fascinating to watch as the male and female will “shimmy” their bodies one after the other as a sign each is ready to spawn.
The female will begin spawning by laying tracks of eggs over the spawning site. The male will then closely follow the female and release sperm over the freshly laid eggs. This will go on for several minutes until the pair has finished spawning. Once they are done, each parent will take turns fanning the eggs with their mouths and pectoral fins. This behavior helps move oxygenated water over the eggs so that fungus or algae doesn’t grow over the eggs. If some eggs are unfertilized, the male or female will eat this eggs. For some inexperienced breeding pairs, this is the time where some parents may accidentally eat the eggs. If this happens, don’t feel too bad, they usually do better on subsequent tries. As the embryos develop, the parents will continue to pick off bad eggs and move fresh water over the lot. After about 50 hours post fertilization, the eggs will begin to hatch.
As the discus embryos begin to hatch, they will remain affix to the side of the breeding cone. They achieve this by secreting a glue from a special appendage located on their head. WIth their head glued to the breeding cone, the newly hatched fry will begin wiggling their tails back and forth. This “wriggling” serves two functions; it moves fresh oxygenated water around the fry and gives the parents a visual cue so that they can see their babies. As more and more wrigglers hatch, the parents will be seen plucking the fry off the breeding cone and spitting them back out. As frightening as it might look, don’t fret too much during this stage. The diligent parents might look like they are eating their young, but some researchers think this process might actually act as a vaccination process in which the parents pass on antibodies and strengthen the immune systems of their young this way. After about 8 days post fertilization, the discus fry will become free swimming.
About the time when the fry became free swimming, their yolk reserves ran out. Luckily for us and the fry, the parents will take over the feeding duties. Both parent discus secret a nutrient rich mucous along their flanks which will be used to feed the fry for the next several weeks. It is believed that this secretion helps transfer immunities and resistances to diseases from the parents to the fry. The fry will be seen swarming the discus adults like a cloud, constantly feeding on this mucous. Watch carefully as you feed the adult discus during this stage as they may not be interested in taking food. After a few weeks, the adult discus will start to produce less mucous and it becomes time to start weaning the fry onto other diets. A great first food to offer the fry is freshly hatched Artemia nauplii. Live artemia are rich in fats and amino acids and will help the fry grow quickly. In addition to artemia, try offering fine grade flake foods as well. After about four weeks of feeding off the parents and receiving supplemental food, the discus fry should be about the size of a dime and can be moved to a separate tank.
Once the fry are weaned off the parents, they can be moved to a separate 10 gallon tank. In this small tank, it will be easy to target feed the babies and they won’t need to expend a lot of energy swimming around for food. At this point, you should still be doing daily water changes, but you can slowly start to bring you conductivity back up to normal levels. At this point, you can sit back and enjoy watching your fry grow up. Be sure to offer them a variety of foods in small amounts several times a day to ensure they grow properly. You can supplement the artemia and Depending on the number of fry that have survived to this point and how big they are, you may need to start moving them into larger tanks or finding them new homes!