Within the realm of freshwater fishkeeping, supreme royalty is ordained to discus. Discus embody refined beauty, amazing intelligence and distinct personality. For these reasons, their husbandry has the allure and romanticism of an Indiana-Jones-finds-Atlantis-style challenge. Their sensitivity to system parameters, such as water chemistry and temperature, have bridled them with the reputation of being nearly impossible to keep--BUT, although they are demanding, they are far from impossible. This, however, is true with most aquatic myths. In the marine arena, certain butterflies & angels, most sweetlips, almost all anthias and, of course, moorish idols come to mind--all easy to care for over many, many years if you know what you're doing and are attentive to detail. But enough on that; suffice to say, discus live for attention (don't we all!) Millions of these wondrous fish are bred in captivity and sold every year. But before we break into specifics on their care, it is important to understand a little bit more about discus as they are found in the wild.

Discus (Symphysodon aequifasciatus) are, first and foremost, cichlids (pronounced SICK-lids). They belong to one of the largest families of fish on earth, family Cichlidae. The incredible diversity and geographic span of this family includes such notables as the ever popular Oscars, aggressive Jack Dempseys, Red Devils & Green Terrors, brightly colored African Rift Lake inhabitants, beautifully finned freshwater angels and many South American dwarf species. All cichlids are highly intelligent; therefore, invariably they are excellent parents (now why didn't that stick with other species?) Cichlids care for their young to a degree not found in most other families of fish, which is one of the things that makes them so appealing.

Discus originate from South America, specifically the Amazon basin. They are found in the Amazon River and its major tributaries, including the Rio Negro, Rio Madeira, Rio Tocantins, Rio Tapajos, and Rio Xingu. They are found in the shallow waters near many large cities, several of which have lent their names to the color strains of discus found there, including Belem Brown, Manacapuru Blue, and Santarem Green. However, the Latin name of standard discus (aequifasciatus = equally striped) refers to the nine equally spaced vertical bars that discus exhibit when they are excited or stressed.

All the rivers previously mentioned are typical South American blackwater environments. Blackwater is so called because of the rich brown color it obtains from the dissolving organic matter over which it flows. This organic bed softens the water by absorbing other dissolved salts and replacing them with humic and tannic acids. This lowers the pH and conductivity of the water to a level that is very difficult to recreate. An average blackwater sample would have a pH of roughly 6.0 and a conductivity of less than 30 microsiemens, or roughly 1 degree GH. Although considerable variability occurs from these numbers in the wild, these are the constants we should strive for in captivity. This brings us to the challenges involved with keeping discus anywhere outside of their natural environment.

There are three doors to pass through before you enter the world of successful discus husbandry. Water chemistry, mentioned previously, is the first and most important lock to pick. How does one go about recreating the environment mentioned above in a captive ecosystem? In the not-so-distant past, peat was the primary accomplice. Peat softens water and lends brown coloration too. Although it works wonderfully well and to-date remains a very good choice, many hobbyists don't appreciate tea-stained beauty. For those aquaticians, technology through the miracle of reverse osmosis and deionization (see Help on RO/DI Water Purification) has moved us beyond the peat-dilemma. Water produced by such a unit is purer than that found in any body of water on earth (not sure about middle-earth though!) This, however, is not necessarily good, as it is roughly analogous to breathing pure oxygen. It will work, but not well and not for long. RO/DI water must be reconstituted (means remineralized/ electrolytes replenished thereby raising the GH--without adding salts) using a product designed specifically for that purpose, such as Seachem's Equilibrium. Such conditioners should always be used when initially establishing a discus system. However, as the ecosystem ages, the small amount of decaying organics produced by live plants will replenish the dissolved solids in the RO/DI water used for water changes. This is one of the reasons we do not recommend keeping discus in non-planted aquaria. Without plants, water chemistry is much more difficult to maintain. Also, plants provide hiding places for discus; they can be easily stressed without such security. RO/DI water has a pH of 7.0 and no measurable conductivity. From this starting point, it is much easier to raise the hardness than to lower it. However, dissolving organics along with the acids contained in fish waste have a strong tendency to depress the pH in such soft water in closed systems. This can be controlled with chemical buffers, but usually not without raising the hardness to unacceptable levels... which brings us to door number two: YOU MUST PERFORM WATER CHANGES!

The importance of water changes cannot be overstated. The most effective way to combat the natural biological tendencies of pH depression and rising hardness in an established tank is through frequent, large, routine water changes (hmm... where have we heard something similar before--see Help on Water Changes). The water change rule of thumb for freshwater aquaria of 5-10% weekly or 10-15% biweekly is out the window. Dedicated breeders advocate changing 40% - 50% of the tank volume daily. While this may be necessary to maintain and breed truly wild-caught specimens, cultivated color strains that are often fifty or more generations removed from their original wild parents are much hardier than their wild cousins. We perform roughly a 50% water change weekly. Although a bit of a chore (when you consider all our discus systems and the 200 gallon show tank), it is an easy way to keep the pH up and the hardness down. Because such large water changes can cause undue stress on the fish, all replacement water is reconstituted, aerated and heated before being added to the systems. We strongly recommend you take these extra steps to ensure the vitality and longevity of your aquatic mates--again, don't be lazy here!

The final door to pass through for amazing success with discus-keeping is luckily the easiest to access. Anyone who has been to South America will tell you one thing: ¡Hace mucho calor! And the humidity doesn't help! The average temperature of tropical freshwaters worldwide is roughly 78 degrees F. However, the average water temperature of the Amazon basin is 82 degrees F. This should be viewed as the minimum system temperature for discus. For optimal health and breeding readiness, one should strive to maintain a temperature of roughly 85-86 degrees F. This is easily accomplished with submersible heaters--and remember, especially with discus, heater redundancy is very important. Use the guideline of 7 watts per gallon (instead of the usual 5 watts per gallon) with discus and make sure this is split between two or more heaters, depending on the size of your system. The only time the temperature should drop is as a precursor to spawning. One of the easiest ways to encourage discus to spawn once you have an established pair is to do a large water change without pre-heating or reconstituting the water. The sudden chemistry and temperature shift will trick the fish into thinking the rainy season has come. This is best accomplished in conjunction with a drop in atmospheric pressure, i.e., when a storm front comes through your village! This works to entice the fish to spawn most of the time. The water will warm up over the next few hours and healthy fish can handle the change with ease. Note that this maneuver should not be performed more than once every 6-8 weeks... but breeding is another topic.

The parameters we have addressed thus far are not the only considerations for establishing and maintaining a thriving discus kingdom. Diet is critical also, as we have discussed before (see Help on Fish Feeding & Nutrition). In particular, discus love bloodworms, glass worms and daphnia--frozen and soaked in Freshwater Zoe & Zoecon or Selcon, of course. There are also some great dried foods specifically formulated for discus--Sera has a few that come to mind (red & blue variety granules--both of which we carry). Tankmates and lighting intensity are also factors. But those points can be debated. The three doors we entered above, however, are generally agreed upon universally to some degree: 1) RO/DI water provided new opportunities in discus-keeping (unless you like tea); 2) frequent, large, routine water changes with appropriately conditioned water keeps success at your fingertips; and, 3) discus like it hot, and these guys don't sweat when the heat is on! Follow these simple guidelines and you can look forward to a long, happy life admiring the Royal Family of Fish.