July 29, 2004
Discus Breeding
Breeding discus is still quite an achievement for the aquarium hobbyist but also one of the most interesting aspects of keeping this beautiful fish. The view of a couple of mature discus fish swimming around with their offspring is really fascinating. The discus has an unique way of feeding their young, they produce a skin secrete that is the only food source in the first couple of days. Right after the young fish are swimming free they start to graze their parents, if one of the parents is consumed, well the skin secrete, they well be transferred to the other parent. But before you see these wonderful youngsters and their parents swimming around there are a few guidelines to take care of.
Partner selection
In my opinion it is best to start with a group of semi-adult fish and let a couple select themselves, don't believe the couples for sale in a lot of petshops. Often they are just two mature fish and a discus couple is really something different, discus are very picky when it comes to their partner choice. That's quite normal in the animal world when a couple have to depend on one an other in raising their young, and discus are no exception. When a couple is formed within a group of discus fish the change of getting a successful breeding couple is much better.
Water conditions
For discus breeding the water hardness and PH value are very important, be sure to keep the values as close as possible to the optimum, otherwise the discus will spawn but the eggs will not develop correctly.
The optimum water conditions for breeding are:
Temperature: 31°C ( 88°F )
Hardness: 3-10° dGH
Ph: 5.5-6
A breeding tank?
If you need a special breeding tank depends on a lot of factors. Are the discus kept by themselves or do they have other species as tankmates. You can imagine that if other species of fish are present they can disturb the couple and/or feed on the young. The discus will try to protect their young but in the limited space of an aquarium that is hard to achieve. If there are only discus fish present and the tank is not overcrowded you have a good change a couple can raise the young within the tank.
If you want to raise as much of the young as possible and want more control on the water values and other variables, a special breeding tank is the preferable. This way the couple can solely concentrate on their care of the young and it makes the feeding and cleaning for the hobbyist much easier. I personally like the more 'natural' breeding method within the regular discus tank. You will probably loose some of the young, but the behavior of a breeding couple within the group is worth it.
The eggs
The discus couple will find a suitable place ( plants, aquarium window or any other vertical place ) to deposit their clutch of eggs, the amount of eggs ( 50 to 200 ) depends on the size of the female discus. They start cleaning the place very carefully and often the surroundings as well, this is part of their mating behavior. While cleaning the place, they shake their heads and often are aggressive to curious tankmates. When al the cleaning and shaking and stuff is done the female will start laying her first row of eggs, the male discus follows behind her to fertilize the eggs. The eggs will hatch in about 60 hours.
To raise the young discus you need to start you own little Artemia factory, more information about artemia as a food source here.
Posted by Front at 11:30 AM
Discus Fish colors
There are 4 'real' discus variants, with their own Latin name. The rest of the color variants are captive bred and the list of these color variants is nearly endless. They have exotic names like, 'Snake Skin', 'White Diamond', 'Blue Diamond' etc... The color variants displayed here are just a few examples, more will be added in the future.
 Brown Discus Symphysodon Aequifasciatus Axelrodi |
 Blue Discus Symphysodon Aequifasciatus Haraldi |
 Green Discus Symphysodon Aequifasciatus Aequifasciatus |
 Heckel Discus Symphysodon Discus |
 Discus "Red Ruby" |
 Discus "Red Ruby" |
 Discus "Blue Snakeskin" |
 Discus "Yellow" |
Posted by Front at 09:31 AM
Water conditions
Discus fish come originally from the Amazon river, this water is soft acidic and has a brownish color. The water generally has a temperature between 26 and 31 °C ( 79 to 88 °F ) and a PH range of 5.5 to 6. The hardness of the water ranges from 3 to 10° dGH.
For the aquarium it is not necessary to imitate these values exactly, except for wildcaught animals that are recently imported. They are very fragile when in comes to water quality and the hardness of the water, captive bred fish are much more tolerant. I would recommend to try to keep the water conditions as follow:
Hardness: between 3 to 15° dGH
PH: Between 5.5 and 7
Temperature: around 30°C (86° F)
To lower the hardness of the water I would not recommend to use the supplements offered in petshops. The main reason for this is that the effect will not last very long because of the regular water changes. In my own tanks I use peat in my filter to lower the hardness. But there are other methods as well, which I will discuss at a later point.
Nitrate and nitrite levels
Besides the hardness of the water it is very important to keep the nitrate and nitrite levels within an acceptable range. I would not let the nitrate value come above 20 and the nitrite level is ideally not measurable. This is achievable by using a good filtering method, the right amount of fish and a regular change of 1/3 of the water. For my own tanks I change about 1/3 of the water two times a week. I use normal drinking water for this purpose, but I am lucky to live in an area where the water values are within an acceptable range.
Oxygen and CO2
When it comes to discus fish and temperature there is one last issue to mention. When you keep your fish at lower temperatures they become more susceptible to diseases. Because warmer water contains less oxygen it is important to have enough water surface movement. This way the water can better absorb the oxygen and get rid of waste products like CO2, 'real' waterplants like Vallisneria, and Ceratophyllum also have a positive effect on the oxygen/CO2 levels. If you like you can also use an Airstone, in combination with an air pump.
Posted by Front at 12:19 AM
July 28, 2004
Aquarium filtering
Talking about water conditions, to keep the water clear and healthy a good filter is needed. There are several ways to filter the aquarium water. The best filtering method is a biological filter, but that's not always an option, depending on where and how the aquarium is placed.
A biological filter is basically a smaller tank under the actual aquarium. In this 'filter' tank the water goes through several compartments with filtering substrate, where large colonies of cleaning bacteria will develop. Besides the positive effect of the bacteria a biological filter larges the overall volume of the water, which makes the water quality more stable. The effect bacteria have on the water quality is not limited to a biological filter, all filters will contain the positive bacteria over time, but because of its larger size the effect is just better.
There are two other kind of filters often used in our modern aquariums, for smaller tank sizes there are often small inside filters used. They have a rather small capacity and can over time become a problem because the waste products are remaining inside the water. I would only recommend these inside filters for temporary usage, like for a breeding tank or a quarantine tank.
The most used filter is an external one. If you buy one with enough overcapacity it is a good filtering method. Be sure to clean the filter substrate every two months by washing it out with water of the same temperature ( more or less ) as the aquarium water. This way you will get rid of the waste products without loosing all the bacteria.
Posted by Front at 08:18 PM
The Aquarium
Discus fish are large fish and should therefore be kept in a big aquarium, about 50 liters ( 13 gallons ) for one mature fish is a good guideline. Because the discus is a schooling fish it should be kept in small groups with a minimum of 5. If we calculate a little further we come to the conclusion that a tank of 250 liters ( 66 gallons )is a minimum size to start with. The discus is a high shaped fish and when selecting an aquarium a higher tank is recommended.
That discus should be kept in a 'clean' tank, meaning without decoration, is a myth and in my opinion it always has been. To stimulate normal behavior and to reduce stress it is best to decorate the tank as natural as possible. An aquarium with large plants, some rocks, roots and a few floating plants is the ideal setup for the discus. It provides hiding places, filters the light from above and contributes to a healthy water condition.
The standard light tubes used for aquaria are sufficient for a discus tank, be sure to create some dark places in your tank where the fish can hide.
Posted by Front at 08:05 PM
Discus background
The Discus is a large cichlid form the Amazon river, and floodplanes, in South America. The discus and it's variants are first described in 1840 by Dr. Heckel as Symphysodon discus, this name is now in use for the Heckel discus variant. The three 'original' color variants received their own name, the Green Discus Symphysodon aequifasciata aequifasciata, the brown discus Symphysodon aequifasciata axelrodi, and the blue variant Symphysodon aequifasciata haraldi.
The discus is a social animal. They live in large groups in their native waters, and have a very advanced social behavior, they are one of the few real schooling cichlids. Remember to keep this in mind starting with discus yourself, always purchase a group of animals. They need the social interaction to develop their characterful behavior to it's fullest.
At this time it is rather hard to find the original color variants in pet stores, only the Heckel is sometimes imported. Most of the discus you encounter today are captive bred color variants. At this time the list of described color variants is nearly endless, and personally I thing that's not only a good thing. Some of the discus color variants have lost their stripes and therefore their natural ability to communicate in the school and currently some Asian breeders are working on a discus variant in the shape of a boomerang. But as always these new variants are finding their way to the aquarium hobbyist quickly for exceptional high prices and this will stimulate the breeders to try to find a new one. One of the advantages of the captive bred discus is that they are now much easier, not easy, to maintain as the imported ones. The are much more tolerant concerning water conditions.
Posted by Front at 04:01 PM