Spawning Discus or
The right approach may bring immediate results ! - Part I
by George J. Reclos
I may repeat myself quite often but I will never stop emphasizing that keeping fishes in captivity is - or should be - a very serious issue. The serious and dedicated hobbyist should spend some time reading as much as possible about the particular species he wants to keep - or already keeps - in his tanks and make sure that he has done his best to give his fish the best possible conditions. The term "conditions" covers a wide range of factors which include - but are not limited to - compatibility, tank size, water parameters, filtration and last - but not least - the aquascape of our tanks. There are quite a number of articles on those issues and you can read some of them in the relevant section.
We never claimed that we have a solution for every problem. Whoever makes such a claim must be superficial. What we try to do is to show you how we and others (sometimes more knowledgeable) keep our fishes. After reading all these articles one thing can be concluded. All those people, us included, have had some success in keeping and breeding the fish they keep because they spend some time to learn more about the natural biotope of their fish, as well as about the fishes themselves. In this aspect, Francesco has provided a great deal of first hand information in his articles describing his trips to Lake Malawi in 1997 and again in 1999, as well as his visits to Central America and the Amazon. A lot of useful information can be extracted from those articles if one spends the time to read them carefully. That apart, there is also a wealth of information available either in the internet (you can find many good websites here) or in books (a wide selection of books has been reviewed here). All in all, unless you keep a specific fish which just made its introduction in the hobby, ignorance can't be an excuse.
Oddly enough, if you look at the species most of us (MCH authors) keep you will notice that although there is a wide range of them (Malawi, Tanganyika, Victoria, Madagascan, Central America and some South America cichlids plus a good number of catfishes and - temporarily - even a temperate marine tank) there is one species on which very little has been said. The famous Discus. To some it is the "king" of fishes while others will just pass on. I really can't tell why but it seems none of us has ever grown a serious interest in them and consequently the people we came to know don't keep them either.
At the beginning of summer 2002 (almost 20 months ago) I started my own Discus tank, mainly to satisfy my wife and keep her continuous objections to my "just one more tank" theory to a minimum. The discus were initially placed in a completely unsuitable tank (you can read about this tank here) but were shortly transferred to larger quarters which were adequate as far as size is concerned (240 liters for 6 discus) but the aquascape left a lot to be desired. This was mainly due to the fact that I always regarded this tank as "her" tank and since she has a passion for plants we included every piece of shinning plant - covering as much of the spectrum as possible. Red plants, light demanding plants, heavily eating plants, everything was there. As a result we had to give them too much light, too much carbon dioxide and of course enough fertilizer. Of course, the result was a tank which was quite nice to look at - at least for our taste - but was it good for the Discus fish ? Little did I care back then.. Keeping my other half silent and more tolerant was the main issue.. All I did was to buy some good books on planted tanks, get out my chemistry books, buy some tons of chemicals (old habits die hard) contact a couple of knowledgeable hobbyists with planted tanks and that was all.
Contrasting colors, reds and bright greens and rapid plant growth. Is it a paradise for Discus ?
I can hear you asking: "Where were your many books then ?". You are right, but things are not that easy or simple. Sometimes, the "trend" of the day will carry you with it like a stream. If you look around in most websites, photo contests or even books dealing with "planted tanks" you will see that Discus fishes seem to be an essential element in most planted tanks of some size. Even reputable publications show exactly that. I will also mention that most Discus keepers I know keep their fishes in high maintenance planted tanks. It seems that in their minds the plants are of equal or even greater importance than the fish. Of course if you ask them directly they will deny it, simply because they "think" that such a tank is a paradise for discus. It is evident that nothing could be further from the truth. Discus fish normally live under the roots in the banks of the rivers and prefer shadow to light, not to mention too much light. However, too much light is the key element to have a tank full of demanding plants such as Alteranthera reineckii, Rotala macrandra, Hemianthus micranthemoides, Myriophyllum tuberculatum and Nesaea crassicaulis to name just a few shown in the photo above. The plants were nicely growing but what about the discus ?
You can hardly "squeeze" another fluorescent tube in there. I was about to move to metal halides to ensure even faster growth of my plants.
Discus, like all other fish, can't talk, so I can only guess. However, it is obvious that fish which love shaded areas can't live happily under 8 fluorescent tubes covering almost the whole surface of the tank as you can see in the photo of the tank above. More than 260 Watts of light were supplied to this tank (more than 1 Watt / liter) which made even access in the tank a really tough task (all the tubes had to be removed in order to get anything in or out of that tank). Moreover, the tank was so crammed with plants that I really wondered how did the Discus find their way around. Of course, the fish were small when I acquired them but, thanks to the daily water changes and the exclusive use of deionized water, they gained size quickly. At that time I was setting up my small fishroom and was quite busy so I completely overlooked this issue. However, once the project was finished (for the moment; stay tuned on this one) and the tanks were running smoothly, the Discus issue came back in my mind. It was obvious that this tank should become either a Discus tank or a high maintenance planted one, but not both. The best of two worlds can not coexist in a tank therefore compromises should be made. Since I am not a planted tank addict, the focus of interest was the fish. We had plenty of plants in that tank already so we could easily select the ones which would grow in much lower light levels (Microsorum pteropus "windelov" and many Cryptocorine and Anubia species). Moreover, the addition of generous amounts of bogwood would allow us to attach some of the plants on them and create a far more interesting aquascape which would serve the needs of the discus as well as being aesthetically pleasant.
Microsorum pteropus "Windelov" ready to be tied on bogwood.
While re-decorating the tank we had some nice surprises, too. Due to the high CO2 levels and tons of fertilizers, the small Microsorum pteropus we had placed in the tank at the beginning had grown beyond our wildest dreams. We had added two small pieces and a large one and what we got in return was some huge plants. The plant in the photo above was about 20 cm when planted and now it was more than half a meter across, not to mention that large parts of it had been transferred to other tanks in the meantime. The plant in the photo below barely covered the stone it is attached to when it was introduced in the tank (actually it was a small part which escaped from the larger one). Now, not only was it more than 30 cm in diameter but had also attached on that stone perfectly well. Removing it without damaging it was out of the question so we decided to use the stone as is. Our small Anubia plants had also tripled in size so there were enough of them to cover the "gaps" in the new aquascape.
Although living in the shade, the amount of light was more than enough to keep it growing. Carbon dioxide and 8 doses of fertilizer daily resulted in a beautiful "natural" plant.
Bogwood was the key element in our new aquascape. It was going to be used to create many "caves" and also to support the plants that would make it look more interesting. We were tempted to leave the bogwood naked in the tank (quite interesting as an approach) but we didn't feel very comfortable with the idea of throwing away all those plants. It should be noted that bare bogwood would be the ideal aquascape for the discus, but it is the aesthetics that would - perhaps - suffer. Therefore, Johnny and I decided to stick to the initial plan. The bogwood was previously soaked in boiling water for 24 hours and the water was changed every three hours to remove as much of the brown color as possible before adding it in the tank. The new tank would only have two fluorescent tubes (70 Watts in total) and we thought it would be better for the fish to adapt to the reduced light levels over a day or two. If the bogwood would be allowed to leak all this brown color in the tank immediately the decrease in light levels might even cause stress to our Discus. One must always keep in mind that, unlike African cichlids, Discus are very sensitive fish which can be stressed very easily. Removing all this vegetation and adding the bogwood was already too much for them. During a previous major aquascape project, which was combined with a maintenance of the tank, one of the smaller discus was stressed a bit more than the others - or so it seemed. What we know is that this particular fish never recovered and in a matter of months we witnessed the transformation of a well fed and active discus to a fish wreck, a distant memory of what it used to be. Soon, the other tankmates didn't allow it to eat properly (you have to keep in mind that, unlike other cichlids, discus take a really long time to finish their "meals") or swim in the open and the result was the loss of this fish. What most people fail to accept is the fact that although very "mild" in temperament, the discus is a cichlid. It may be a slow mover, a "fragile" fish if you prefer but when it comes to forming a pair, defending a territory or bully the weakest conspecific in the tank they can work miracles. To avoid this we had two options: either remove the discus beforehand (as described in the re-decoration of Margarita's tank) or do most of the work out of the tank, minimizing the time we would spend working in it.
After examining the situation we decided that a 240 liter tank is much larger than an 100 one and that two fishes are removed much faster than five, not to mention that the construction of this particular tank offered the fish some really nice hiding places which would require repeated efforts to net them. It seemed that getting them out of the tank would stress them much more so this option was abandoned. Therefore, we were left with the second option which was to try and do most of the work out of the tank. We tested all the bogwood pieces on a large table to see which of them would create a nice and stable combination (keeping discus is a great advantage in this aspect) and then attached the plants on the selected parts. Only when the whole work was finished we removed the rest of the plants and then added the new elements. Needless to say that all stones which were in the tank were removed with the sole exception of the one which had the Microsorum pteropus attached on it. The whole process was accomplished by the two of us in three hours while we only spent 15 minutes working in the tank. Going faster than that was simply impossible. Just to be on the safe side we even performed a 50% water change with deionized water and added a small quantity of "stress coat" (which we don't add under normal circumstances) just before turning the lights off. In the photo below you can see a tray with washed and pre-soaked bogwood. Two such trays were used to carry the bogwood used in our new design.
The emergency case and the pre-soaked bogwood ready to leave for the office. The discus tank is the only tank which is not located in our home.
Continued in next page