Firstly, we will turn our attention to the breeding tank size. The ideal standing height for an aquarium for breeding Discus starts at 3 to 4 feet, this being measured from the bottom of the aquarium. Therefore with an 18 inch high aquarium, the height of top rim would be 54 inches. I raise my breeding tanks 12 inches higher than that. From experience, it can be said that fish are not alarmed as readily at this height. This is connected with the angle of incidence of light.
Discus kept in Aquaria at leg height are always noticeably timider. A frightened Discus naturally will not think about breeding. Sometimes fishes in sterile unfurnished aquariums are so alarmed that they race to the sides of the tank and can even die from their injuries this can be observed in fishes starting at 3 months of age.
The Discus recognizes the keeper and is used to his or her calm movements in front of the aquarium. When strangers visit the aquarium quiet is the first commandment. Healthy fishes, which respond readily to food, will inquisitively come up to the glass when a visitor appears. During feeding, they will literally eat out of your hand!
Light also plays a role because a breeding tank contains no plants the light can safely be somewhat dimmer than in a planted aquarium. Choose warm tone lighting when the fish lay fry, or from the time of egg laying onwards, you should leave a small light on all night. Fasten a lamp socket over the aquarium and use a night light which will provide plenty of light. When you turn on the light in the morning you will see the fishes rest motionless on the bottom of the aquarium. If you fed them right away the fishes would not take any of the food and the uneaten food could foul the water. Wait for at least 15 to 30 minutes before you feed your fishes and only after this waiting period will the fishes be active and except the food readily.
When you noticed that the fishes are ready to spawn turn off the filter until the eggs are laid but for no longer than 1 hour. Strong current disturbs the fishes during the spawning and despite differences of opinion can cause eggs to not fertilize properly. In the wild Discus are born in standing water.
housing for breeding discus
Most Discus keepers do not get by with a single aquarium for Discus. The goal of their hobby is to breed these splendid fishes too so a discus breeding installation soon follows. What options do you have for reaching your goal? There are actually two good methods, each with advantages. The first is the separate tank installation where each tank is treated as a separate unit each with its own equipment. The second treatment is where there are many tanks hooked up to a central filtration unit. Both types of breed installations have pros and cons. The one you choose will depend on your taste and your wallet for the second version is somewhat more expensive at the outset but depending upon the ultimate size of your breeding operation may actually be less expensive in the long run.
Individual filter options
Several Aquaria are set up on a shelf. The ideal dimensions for Discus breeding tanks are 20 to 30 inches long, 20 inches wide and 20 inches high. Small deviations are, of course, acceptable because this kind of aquarium is never filled completely it has a capacity of 30 gallons which is quite adequate for 2 adult fish.
What is the best way to filter these aquariums?
Inside filters combined with sponge cartridges have proved effective for this purpose. A good high output air pump for power the sponge filters and inside filters for 4 or 5 breeding tanks. The small motor driven outside power filters are also available on the market these are power filters are hang outside and are driven by a powerful yet efficient motor. If the Discus lead fry, the opening of the inlet tube must be reduced in size sufficiently with a covering so that the fry cannot be drawn into the filter. Small sponge plugs are the best protective covering.
There should be a significant number of times to start. The advantage of these separate breeding tanks is obvious as each aquarium can be tended separately, special water can be put in each aquarium, extra medicines can be used in each aquarium and so forth. A cardboard screen should always be inserted between each aquarium so that the fishes are not always in sight of one another. The rearing drive of notorious egg eaters can be stimulated if an enemy in the form of another Discus lurks in the neighboring aquarium.
The fishes should not be disturbed during the spawning so at this time the screen between the aquarium is quite an asset.
Common filter option
The second option is to set up a closed installation. The aquarium stand side by side but are connected to a common filter installation. All manner of plastic PVC pipes, as well as suction discs, angles T branches couplings and much more besides are commercially available. You can build a filter installation with plastic pipe holes of suitable size of the bored hole in the rear glass of the Aquarium by a glazier. The overflow pipe with a right angle bend is inserted in the hole for safety the bend outside of the water as a hole bored in the top to prevent all of the water from draining out in the event of a power failure. Air enters the overflow pipe and the water no longer flows into the filter the outflow is collected under the aquarium in pipes and from there flows through a coarse filter and into the filter tank.
A fairly large kitchen colander, in which two thin layers of foam are inserted, can serve as a coarse filter tank. Water from all of the aquarium is collected in the first filter chamber, this is the best place to filter with floss. In the second chamber, the water flows over gravel and in the third chamber over small ceramic tubules. The pump which returns the water to the aquarium is in the last clearwater chamber. With these pumps, the hobbyist now profits from that ornamental pond boom. Recently clever pond pumps with plenty of power yet low wattage have appeared on the market. If one of these pumps is located about 30 inches below the aquarium in a filter chamber it is possible to supply three or four aquariums each with a capacity of 50 gallons. If the filter tank is at the same height as the aquarium 5 or 6 aquarium can be served by the pump without problems the filtered water flows through a tube from the pump back to a system of plastic pipe. This pipe is located above the Aquarium. By means of a T-branch and a faucet, also of plastic, a line is run to each aquarium.
In this way each aquarium has, it's own inlet. The flow of water can be adjusted with the faucets so that about the same amount of filtered water runs back into each aquarium. In this manner, the filter circuit is closed again.
These Aquaria have the advantage of requiring comparatively little work. Supplying water is virtually maintenance free. The disadvantage is that outbreaks of disease affect all of the aquaria so, for this reason, it is advisable to combine these filter installations with an ultraviolet lamp. Bacteria are killed by ultraviolet light ultraviolet have two water connections and are inserted in the water circulation after the filter so that the filtered water is sterilized before it returns to the aquarium.
In aquarium serviced by this filter application there is the danger, of course, that fry will be drawn into the filter. It goes without saying that a safety device must be installed. For this purpose buy galvanized wire mesh of appropriate fineness in the Hardware Store. From it, cut an appropriate size rectangle and bend this mesh into a circle, closed in front and insert it into the outflow opening. For this purpose, however, remove the long intake tube in the aquarium so that the sieve sticks only in the hole bored in the rear glass. You can adjust the mesh size to the size of the fry in the tank.
What is the Spawning site
Discus lay their eggs on smooth vertical surfaces. Most fish breeders use a spawning cone. Fish will use the cone but may at times choose a plant leaf, the side of the aquarium or even the heater tube. However clay vases are most commonly provided. Make sure the vases you buy are at least 8 to 10 inches high. If the vase wobbles or the bottom is not completely smooth you should apply silicone cement around the entire bottom and then set the vase on a piece of newspaper. After the cement has dried you can remove the newspaper with water. The bottom of the vase is now soft and elastic and will stand steady.
Large water change is often just the stimulus needed for a pair of ready, but reluctant breeders. Changing the water temperature by 4 degrees, along with the water change is another great way to trigger spawning. Changing the pH by one to 2 decimal places also helps. These adjustments mimic the effect a heavy rainfall in the Amazon which normally precedes spawning in the wild. As mentioned so often, live foods to get fishes into spawning condition. Do not neglect this all important element in Discus husbandry.
Many Discus breeders struggle with fungus attacks on the eggs. Aggressive fungicide treatment, however can interfere with the production of the parents essential food slime, so a different approach is necessary. First why are Discus eggs sometimes attacked by fungus?
One reason is that the male may not have fertilized them, this however, is rare. Another reason is that the sperm may not have had the opportunity to enter the egg. I have dealt with the problem of fungus infestation in many clutches of eggs.
After the egg is laid, the sperm has only about 2 minutes to enter and fertilize the egg before the egg swirls in the water and closes this entrance. If the eggs are fertilized it is attacked by fungus. In the wild, the discus lay their eggs in stillwater this gives them a chance to fertilize the eggs before being washed away. We should give the sperm an advantage in the Aquarium by shutting off the aquarium filter during the spawning phase. This will give the sperm a better chance to fertilize many eggs. Consider that when the female lays a string of eggs and the male releases sperm, but it is swept away by the current produced by the filter, that another 2 minutes may go by before the male returns.
The result is that the egg opening of the first eggs will already have closed and the sperm will no longer be able to enter. Now I must turn to trout eggs. These have a hatching time of several weeks which is dependent only on water temperature. The warmer the water the faster the egg develops. The same is true of the Discus egg. At 82 degrees Fahrenheit the eggs require a development time of about 65 hours whereas at 88 degrees fahrenheit the time decreases to about 55 hours. I have completed tests with a water temperature of 77 degrees fahrenheit and determine that the development period of eggs was 72 hours.
I also discovered that at high temperatures, above 84 degrees fahrenheit, that eggs were more likely to be attacked by fungus than at lower temperatures. This makes sense because fungus prefers high temperatures and also reproduces faster under these conditions because fungus could be present anywhere in a tank, it must be killed.
The trout breeder handles this very simply with malachite Green oxalate which he uses once a week to bathe the fertilised eggs. In this way the trout eggs, which for example have a hatching period or six weeks, are treated with malachite green oxalate 6 times during this period.
The same procedure can be used with discus eggs. Working with rubber gloves to dissolve 1.5g of Malachite green oxalate in 1 quart of water. Use 2 drops of this solution for each gallon of aquarium water in the breeding tank. Administer immediately following end of the spawning phase. If after 12 to 18 hours, either no eggs or only a few have been infested by fungus then this Malachite green treatment is finished. If a number of eggs are infected by fungus then repeat the treatment with half the previous dose. The second dose must however be administered no later than the end of the first or the start of the second day. Malachite green must not be added to the aquarium any later because it also disrupts the production of the skin slime. If you have the opportunity to filter the Malachite green out of the aquarium through activated carbon when the fry are ready to hatch.
Another reason why Discus eggs are infected by fungus is too high salt concentration in the water. The membrane of the Discus eggs can be compared to the leather covering of a football except that the membrane is porous. The bladder of a football which holds air corresponds to a thin layer of the egg membrane. This membrane is semi permeable. High concentrations of salt cannot pass through the membrane small water molecules, on the other hand, can enter. This is because this semi-permeable membrane prevents the large salt molecules in the cell from leaving the inside of the cell as they strive to balance the concentration of salts, water molecules enter the inside of the cell from the outside to lower the concentration of salt inside the cell. This process continues until the pressure created inside the cell prevents more water molecules from entering. This pressure is osmotic pressure. When there are many dissolved salts in the water surrounding the egg, balancing the concentration outside the cell is achieved by drawing water from the egg. The egg shrivels and is no longer viable. Eggs attached to the spawning cone, which do not continue to develop. On the other hand the eggs are not always attacked by fungus they have been damaged by the salty water. The only remedy is partially or totally desalted water. Recently an increasing number of small reverse osmosis installations have appeared on the market. By reverse osmosis almost all of the salt content is removed from the water and the water is also germ-free.
development of the breeding stock
The different Discus varieties can be crossed with one another. This means that by crossing different discus lines, new lines with distinct characters are produced. By backcrossing with fish of the same line inbreeding can be carried out, through which the desired traits can be stabilized. The goal of Discus breeding is to establish stocks with stable colours and forms which produce the desired offspring over a long period of time.
It would be ideal if two similar fish, from two different stocks, were crossed with each other. This line breeding, in which the characters of both original lines are retained, would be optimal.
In pure inbreeding setbacks occur frequently. In the selection of adult breeding stock, the breeder can easily evaluate the traits of the fish, since of course they are already present in their final form. Color, fins and body color can be appraised. Thus, if you ever have the opportunity to buy three or four full grown Discus, each from two related or similar Discus stocks, you have a good chance to put together one or two good pairs.
Discus breeding on a small scale is not particularly difficult and also does not raise any big generic problems. The story is different however if you intend to breed a pure discus line. There are so many different nuances of color in Discus today that it is scarcely possible to keep up with the names anymore. In principle all Discus can be crossed with one another a color variety that is very interesting but is not purebred often results.
If you want to make it your business to breed further such a colour variety in good quantity then you must be prepared to bear considerable expense particularly because a lot of space is needed. A Discus line that has used specific goals cannot be built up with only one or two Aquaria. In the breeding of Discus, line breeding and inbreeding must be distinguished.
Line breeding serves to stabilize the homozygosity of the present stock, with special attention being given to a desirable trait like color, body size or behaviour. These traits are the goal of breeding. In line breeding two unrelated Discus lines are bred. Both lines should have approximately the same traits. Matings are made exclusively with fish of both lines. This means that the first parent will always come from the first breeding line and the second parent from the second breeding line. This prevents the deleterious effects of inbreeding. Nonetheless, consistent line breeding with Discus requires a great deal of space. Imagine that the parents produced about 100 fry. These 100 must be reared to a minimum size of 2 to 3 inches for only then can about 50 percent of these juveniles, those that meet your requirements, can be sorted out. The 50 juveniles must then be reared to a minimum size of 4 to 5 inches. Only then can the beginnings of the coloration be optimally distinguished. Now the body form and any other desired traits can also be perceived.
Consider however how much space is required to have 50 five inch Discus. If the fish are too crowded they will not grow well. Simultaneously, 50 more discus from the second breeding line must also be reared. At a size of 5 inches and an age of about 8 to 10 months another half to two-thirds of these fish can be selected out the remaining Discus, of each line, are reared to full size to be used later for forming pairs. Thus it is necessary to rear at least fifteen to twenty from each line. This takes a lot of space, intuition and patience. Not to mention the expense.
Only now is it possible to sort out the future breeding stock from these 30 to 40 large fish. The breeder will be very familiar with the fish he has reared so he will be able to distinguish females from males with a fairly high degree of certainty and to put pairs together. Discus from two breeding lines mated in this fashion will produce fry that will inherit roughly stable traits.
Over several generations, the colors can be intensified and stabilized through further selection. A Discus breeding stock built-up and pursued constantly in this manner will produce better fish from year to year.
Another possibility in Discus breeding is offered by inbreeding. Inbreeding backcrosses are made between siblings or the parents, or both.This means that, for example, Discus from the F1 generation are backcrossed with their parents.This technique can achieve good results in a short time. Nonetheless after 4 or 5 back crosses setbacks in colour and quality usually occur. The inbreeding of Discus is a way to stabilize particular traits quickly but it is recommended to turn subsequently to line breeding.
In the selection of the fish it should be kept in mind that it is possible to distinguish the sexes with Discus of the same brood. Females are usually somewhat smaller and more delicate in build than their brothers from the same brood. The tips of the fins also provide clues because the fins of males taper more to a point where as those of females are more rounded at the tip.
It would be ideal if 8 large discus were given the opportunity in a large aquarium to form pairs on their own. This also requires some patience however because the fish will not always cooperate immediately. Naturally at least two spawning cones must be offered. The other option is to purchase at least 10 fry from a brood and to rear them with a second group of similar fry from a second line. Clearly this takes more time. A Discus takes about a year to reach breeding age. From a school of 20 fry you can select the 10 or 12 best after six months and rear them to maturity.
It is preferable for the pairs to form on their own because then it can be expected that they will also tolerate each other during brood care. It is also possible simply to put pairs of adult Discus together in an aquarium. Whether it actually is a pair is not easy to determine. If the two fish tolerate each other then it may have succeeded. This does not mean, however, that the pair will spawn together. With Cichlids, and especially Discus the fish must be compatible. Merely confining them together achieves nothing. I have made such attempts in part involuntarily.
When 1 male of a good pair died I offered the good breeding female, which had repeatedly reared fry, to three different males in succession but none of them was accepted. No clutches were produced with these three males. Although the fish tolerated each other and were together for at least 2 months no preparations for spawning occurred. Good breeding pairs have a harmonious “fish marriage”. Because Discus do not spawn continuously the whole year the breeder should have patience with the fish. The breeder should leave the pair together not tear them apart immediately should a pair happen not to produce a clutch within a few weeks.
Ideally Discus pairs should lead and tend the brood together. The fish alternate in feeding the fry with food slime. Occasionally however the parents fight over the fly. This is a difficult problem for a Discus breeder because the entire brood can be put in peril. Removing one of the parents can be helpful but can also have the opposite effect. Once the fry have reached the free swimming stage, one parent can be taken out if they fight. It is more difficult if the parents fight over the clutch and eat the eggs. Discus are notorious egg eaters. Egg eating can subside but these fish are usually permanently lost to breeding.
How to tell which is male or female
This is certainly a question for which there is no pat answer. Unfortunately, the Discus has no reliable sex characters. Only during actual spawning is it possible to distinguish the sexes reliably on the basis of the form of the spawning papillae. The Spawning papillae of the male Discus is shorter and tapers to a point, whereas, the spawning papillae of the female is longer and blunter.
Experienced Discus breeders can distinguish the sex of their fishes with a fair degree of certainty. Differentiation is also easier if fish from the same brood can be compared with one another. A popular sex character which however is not absolutely reliable is the more pronounced forehead of the male. If the fish has more pronounced head area maybe even a slight hump it is usually called a male. When viewed from the front, the head of the males are broad and rounded to the outside. Females, when viewed from the front, have somewhat narrower heads. Fishes with protruding lips are often classified as males too. Elongated straight pectoral fins could also indicate a male.
A somewhat more reliable character is the shape of the dorsal and ventral fins. The ends of these fins are rounded in females whereas males have more tapered fins. The dorsal fin of males is also curved more on top and the ventral fin is curved more to the bottom. The width of the tail fin also provides clues about sex. It is wider in males than in females.
The behavior of Discus in the aquarium can also provide clues about sex but it is not true that the male is always the dominant fish in the aquarium. Females, even those that are smaller than the males present, can rule a discus aquarium. Females exhibit the dark vertical bars more often than do males. It is beneficial to observe the fish for a fairly long time and to study them closely. Then it is easier to make a sex determination on the basis of behaviour and the external characters. This simplifies the selection and cohabitation of pairs. The behaviour of the fish will show whether or not the selection was correct. A true pair will reveal itself by the mutual behaviour of the fish. Now the attacks diminish perceptibly, the fish let each other feed without interruption. This is a very good sign and ramming becomes less and less frequent. A dominant male will certainly stimulate the female to spawn and he will use force if necessary.
One of my discus pairs repeatedly played out this splendid behavior. This pair has already reared many broods successfully and were very good parents. In the times between preparations for spawning the female always had to suffer a great deal. The male always wanted to breed again as soon as possible but the female was not yet able. The male rammed the female repeatedly and continually drove her into a corner of the aquarium. At feeding time however the female was always allowed to take part and feed without disturbance. After that she had to return to her corner. After several weeks however when she had started to produce eggs again the situation changed abruptly. She suddenly started to become an equal partner. In full splendor she hovered in the aquarium and allowed herself to be courted. Now there was absolutely no more ramming, only affectionate circling by the male. It did not take long before they spawned and cared tenderly and resolutely for the clutch and larvae.
Successful Discus breeding
Once a pair has formed it will spawn. The colors of the fish change in the preliminary stage of spawning. The fish turn darker more so in the rear part of the body. The last 4 vertical bars become clearly visible whereas the transverse stripes in the front part of the body remain light. The stripes on the front part of the body disappear completely and only the stripe across the eye remains visible. The fish stay at the spawning cone and start to tremble. This trembling is a twitching and shaking of the head. The next phase of spawning is cleaning. The fish rigorously suck the from the spawning cone. This intensive cleaning indicates that spawning is imminent. The females spawning papillae or ovipositor now becomes visible. This broad Ovipositor is clearly visible because it is about 3 to 4 mm long the males reproductive organ is shorter and slightly pointed. Soon the female, in particular, starts to test for egg laying. She examines the spawning cone from bottom to top. Now it is hoped that the male will no longer allow himself to be warded off and we'll wait for the female to finish testing the cone. This can take up to an hour and to begin laying eggs.
The female swims up to the spawning cone from below and lays a row of eggs. Now it is beneficial for the male immediately to swim after the female and fertilize these eggs. The female moves faster and faster and lays row after row of eggs. Medium sized clutches have about 150 to 200 eggs. The largest clutches can have up to 500 eggs. The spawning process last about an hour.
Watch the fish while they are spawning. They will paint the picture of perfect harmony. The sexes are easy to distinguish at this time which could perhaps be very useful with a later change in mates. After the eggs are laid the parent stay by the eggs and fan them with their pectoral fins. Harmonious pairs take turns. You can safely feed the fish during this phase but you should not offer too much food. This is so that leftover food does not foul the water. The fish also do not eat as much now as usual. It would be wrong however not to feed them during the entire breeding time. Perfect Discus eggs are clear. The larvae hatch after a period of about 60 hours. This time can be reduced if the water is 86 to 90 degrees Fahrenheit. The ideal breeding temperature is 84 to 88 degrees fahrenheit.
After an additional 50 to 60 hours, the wriggling larvae start to become free swimming. As the larvae hatch they are sucked out by the adults and are usually moved next to the clutch. They hang there by a sticky thread. Larvae that become free swimming prematurely are gathered up by the parents. In so doing the parents seemingly eat the fry but then swim back with the escapee to the brood and spit it back into its school of siblings. As soon as the fry are free swimming it is important that they swim to the parents for only then will breeding be successful. If they do not find the parents skins slime, but instead swim around in the aquarium, they will soon perish. The reason for this aberrant behavior is unknown.
In the first 4 to 5 days the fry feed exclusively on the parents skin slime. The term slime is loose, actually the Discus fry are ingesting the entire epidermis of the parent except for the base where it is formed. If you look closely you can see how much energy the young fry expend tearing off the shreds of tissue. In the digestive tract of the fry everything that they have eaten can be found more or less digested epithelial cells, secretory cells and the bacteria that live on the parents skin. There is also evidence of other food such as diatoms thus intestine, even at this early age, contains not only the parental slime but food from the aquarium as well. Parental feeding of the young is one of nature's inventions that considerably increases the success of Species. It increases the effectiveness of brood care reduces losses among the young and opens the way for smaller broods. This is evolution however there is a payback. This ability of Discus to provide food for their newborns has in a sense weakened them. Their skin is not the defensive weapon it is in less evolved fishes. Fine skin is more easily damaged by bacteria and parasites. That is why discus must be kept in a relatively germ-free, but not sterile Aquarium. Bear in mind that along with the slime, the fry are subsisting on the bacteria that live on that tissue as well. This Discus milk is unique and incomparable food for their fry. If you think about the benefits of maternally nursed human infants you will see that there are many benefits especially for the immune system. The development of the slime is induced by hormones. The proper functioning of the hormonal system is strongly influenced by emotional health and diet. Stressed fish cannot produce the food their fry need. Think about this before you show your breeders to visitors!
Caring for the Fry
Convincing Discus to breed is usually not a problem. A good pair does all the work. The eggs are laid hatch and soon grow into free-swimming fry this is when the fish breeders real work begins
Feeding the Fry
Four or five days after the young become free swimming, they are fed freshly hatched artemia nauplii. Soon you can feed prepared foods for baby fishes or moina (miniature daphnia) but continue to feed artemia for a while. On this diet the fry will have reached the size of a quarter after four weeks. At this point they can be taken from the parents. After a total of 6 to 8 weeks they will have reached the size of a half dollar and can already be sold.
Rearing the Fry
After 3 to 4 weeks the small Discus has reached the size of about 1 inch and must be separated from the parents. Now the real problem of Discus breeding begins, namely the successful rearing of the fry. An aquarium full with ravenous little discus is hard to care for. The water must be monitored constantly with regular partial water changes and this does not mean once a week but daily are necessary.
Discus fry, in this stage of development, must be fed several times a day with first-rate rearing food is a prerequisite. A balanced combination of different food is best. Essential, and this cannot be stressed often enough, are regular partial water changes by means of water changes. Toxins, food, remains, excreta from the fish and so forth, are dependably removed.
In the stronghold of mass discus breeding in Southeast Asia, 70 to 80% of the water is changed in the rearing and breeding tanks because this would present us with a real energy problem it is recommended to change about 10 to 20% of the aquarium water daily when fry are present. The rearing water does not have to be softened either, medium-hard water can be used here without further ceremony. pH can also safely rise to neutral levels. Many Discus breeders even claim that their fry grow much better in medium hard than in soft water. I can confirm this. I think that a higher mineral content of the water has a positive effect on the growth of fish. It is also unnecessary to rear Discus fry at temperatures of 86 Fahrenheit. Temperatures of 81 to 82 degrees Fahrenheit are quite satisfactory for rearing purposes.
Fish take up minerals, trace elements and vitamins not only in food but also directly through contact with the medium of water. These substances are of great significance for satisfactory growth. In any case the offered food should be fortified with trace elements and vitamins. Preparations with vitamins and minerals mixtures are commercially available. If you prepare your own food mixtures, in any event you should provide for an adequate supply of minerals and vitamins by administering preparations of this kind. An overdose is scarcely possible.