Water parameters.
It is known that in their native habitat, discus fish live in soft water with a slightly acidic or close to neutral active reaction. However, aquarium experience with these fishes shows that water hardness and pH are not of primary importance; the only crucial factor is that these parameters remain stable. Recommendations for selecting the best water parameters practically achievable in an aquarium vary within a fairly wide range. However, more and more authors agree that the most favorable environment has a pH close to neutral (5.5-6.5) and dH up to 15°.
In the aquarium, water should be soft and preferably acidic, as in natural conditions, but discus fish adapt very easily to new conditions; the main thing is that these conditions are constant. It should be noted that discus fish feel and grow normally in water with parameters noticeably different from neutral. However, they will not spawn in such water. Acidic and soft water is definitely necessary for breeding discus fish. What should one be guided by when creating optimal conditions for keeping discus fish?
The desire of enthusiasts to bring aquarium water parameters closer to natural ones most often boils down to attempts to lower the pH level. The answer is simple and roughly as follows: be content with what flows from your tap. Any attempts to change water parameters in one direction or another will not bring you significant gains, but will only add problems. At pH 4.5 and below, the eyes of discus fish become cloudy from irritation caused by the acidic environment. In healthy fish, this disappears almost without a trace a day or two after conditions normalize, while weak and sick individuals suffer longer and do not always fully recover, so acids must be handled with care.
In addition, an important feature of water should be taken into account – its ability to self-heal. This is especially true for hard water. For example, by diluting tap water with a pH of 7.5 by 50% with distilled water and thereby lowering the pH to 6.5 or even lower, you can be sure that after a few hours the pH will return close to the original 7.5. Moreover, the transition will not occur linearly, but somewhat differently. There you have a serious acid shock for discus fish.
Methods for reducing water hardness have long been known (dilution with distilled water, use of ion-exchange resins during water preparation, simply boiling water for an hour). But do these labor-intensive operations provide tangible benefits to discus fish? That is not even a question. Instability of parameters will occur again. By significantly lowering water hardness, you thereby “kill” its buffering capacity to self-heal. With a slight balance disturbance in the aquarium, the water pH will tend to shift in one direction or another, and since there is no or almost no restraining component (buffer), these pH changes will be quite noticeable. In addition, I can add that according to numerous observations by amateurs and professionals, in hard water rich in numerous chemical elements, discus fish even become brighter and grow better.
Tip: if, despite your creative manipulations, it so happens that the pH has changed significantly and this is already visible in the behavior of the discus fish (secretion of mucus, darkening of coloration, sickly appearance), do not try to forcibly restore the aquarium water. This will further worsen the condition of the fish. Perform any restorative increase (decrease) in pH in several steps, following the golden rule – no drastic changes! And it is best not to touch anything anymore. Healthy fish will recover in a couple of days, and this will serve as a good lesson for you.
In fact, the whole truth lies in something simple – discus fish just need clean water, even if it is alkaline and hard, but definitely clean! Through daily water changes, it is much easier to reduce the dangerous level of ammonia and other toxins (the biological filter works at full capacity in such water) than to resort to all sorts of tricks to recreate the Amazon biotopes.
Only one thing is irrefutable – water changes are vital for discus fish. No state-of-the-art filters and numerous “reparative” additives will spare you from the elementary and tedious procedure of water changes. Water changes and substrate siphoning are performed depending on the stocking density of the fish. Under standard stocking conditions, 20% of the total aquarium volume 2-3 times a week is sufficient; juveniles need more frequent changes for growth: 20% daily. Water procedures should preferably be carried out 1-2 hours after the last feeding.
A common mistake: after 3-4 days of noble laziness, there is a desire to “compensate” for what wasn’t done, and an inexperienced hobbyist performs a 75% water change instead of the usual 20-25%. The result will not be long in coming. If it so happens that there has been a break of several days, it is better to additionally clean the filter and put carbon in it (or replace it), and leave the water change rate the same or increase it slightly. There is another method, difficult to implement in amateur conditions – a closed-loop system with a powerful water treatment unit. But even these figures will ensure success only if the body of water is equipped with a filtration system that provides high-quality and effective water purification (necessarily with biofiltration elements).
One way or another, when determining the frequency and intensity of water changes, the following main factors should be taken into account: • the type and power of the filter used (if powerful biological and mechanical filtration is present, the frequency and intensity of water changes can be reduced to a reasonable minimum); • aquarium volume and its stocking density (the larger the aquarium volume and the lower the stocking density, the more favorable and stable the environment – another way to reduce the number and frequency of water manipulations); • chemical characteristics of the water itself. Secondary factors include water temperature: the lower the temperature (the lower limit of the range for discus fish is 28°C), the slower the processes of food decomposition (food residues), the type of food used, feeding frequency, and much more. However, abusing the advantage of low temperature is not recommended.
It is very important to keep the levels of ammonia, nitrates, and nitrites normal. To do this, you will need to periodically test the water. To ensure cleanliness and a stable hydrochemical regime, mechanical filtration filters with activated carbon are usually placed in the aquarium; it is recommended to use at least 5 grams of carbon per 1 liter of water. In addition, an external filter is used for the most rational filling.
A coarse-pore sponge is laid down as the first stage, followed by a finer-pore one. This is mechanical filtration. Then biosubstrate is laid down (this can be special branded material with a very large specific surface area, ceramics, lava). This is biofiltration. After this compartment, a fine-pore sponge is placed. Then, if the design and filter volume allow, activated carbon or zeolite is laid down, which needs to be replaced every 2-6 weeks (depending on the biological load and fish population). This is chemical filtration. At the outlet, a fine filtration filter is installed (this can be filter floss or a branded fine-fiber pad).
Rinsing of the first-stage filter medium should be carried out regularly as it becomes dirty. Cleaning of the remaining filter materials is carried out less frequently (intervals are measured in months) and in a very gentle mode that ensures maximum preservation of beneficial bacteria – the main capital of the filter.
Lighting.
Lighting in aquariums with discus fish should be slightly subdued. Unfortunately, under such lighting, the coloration of discus fish suffers significantly, especially if peat moss is additionally added to the water. Discus fish look much more attractive when illuminated with specialized spectral lamps such as “Power-Glo” or “Life-Glo”. Under such light, discus fish whose coloration features gray-black-blue “dusting” against a background of primary yellow-orange sparkle with amazing bright blue strokes. And ordinary turquoise ones become truly “royal” turquoise. In many ways, this is a matter of the hobbyist’s taste and the color of the discus fish themselves. For breeding, lighting should be round-the-clock. Any low-power incandescent lamp installed at some distance from the aquarium is quite suitable for these purposes.
Temperature.
The temperature range for keeping discus fish is quite narrow – 28-32°C. The most optimal temperature is considered to be 29-30°C. At lower temperatures, the probability of disease increases sharply. The maximum temperature (during treatment) can reach 34-35°C for several days. When subsequently returning them to the usual 29-30°C, the fish may refuse food for some time. After 1-2 days with intensive water changes, everything recovers. It is undesirable to set the temperature to 28°C for discus fry. It is preferable to maintain 30°C or slightly higher. Fish maturation depends on a number of factors, including: temperature (the higher the keeping temperature, the faster the fish mature), and aquarium volume (the larger the volume, the faster they grow). Experienced discus breeders do not recommend keeping future breeding stock at elevated temperatures to accelerate maturation.
When keeping discus fish in a tank with live plants, aquarists typically maintain the temperature at 28°C, but it must be remembered that this value is the lower limit for comfortable keeping of discus fish, and water quality requirements increase accordingly. To maintain a stable water temperature, aquariums are equipped with two heaters featuring thermostats.
At high temperatures, oxygen dissolves much worse in water. Oxygen is necessary not only for the respiration of the discus fish themselves, but organic matter is oxidized thanks to oxygen. Therefore, it is advisable to supplement the aquarium with an air pump. In fact, the filter provides air supply, but it is not efficient enough in the case of discus fish – an additional air pump is still desirable at high temperatures.
Plants in an aquarium with discus fish.
