Known as “King of the Aquarium”, Discus fish are known to rival marine fish when it comes to beauty, shape and colour. They derive their name from their laterally compressed and nearly circular body shape, and they are large cichlids. Their eyes are usually deep red.
All Discus fish variants originate from the Amazon region in South America, where they are found in lakes, deep puddles and smaller rivers and streams, in soft and acidic waters (ph 5.0-6.5) with minimum current and a warm temperature, at approximately 29°C. The water there looks like strong brewed tea, due to the large amount of wood and leaves releasing tannins into their habitat. In the native habitat, wood and rock is greater in concentration than plant life, most of the plant life being lilies, other floating plants and Amazon swords.
THE WATER AND THE TANK
You should therefore provide your Discus with a pH between 6.0 and 6.5. It is also important that you keep the water in the aquarium soft, 0-3dH is recommended. Discus like to stay in the shadow during the day and the ideal water temperature in the aquarium is 25-29°C.
When keeping Discus fish, it is best to keep them in a species only tank, due to their strict requirements. Also keep in mind that Discus should be kept in an adequately sized, and preferably higher than usual tank. A tank of 250 litres is really the minimum size to start with. Discus also do better in deeper tanks – because the more water the tank holds the more stable the water conditions tend to be. We also recommend that you use an external Canister Filter, as this filter will keep the water crystal clear and it also has a large surface area for biological filtration. The tank should be positioned away from direct sunlight to avoid excess algae and heat. A quiet corner is ideal, especially if nothing goes on above the tank. Discus fish are bothered by movement above them, and this may cause them undue stress.
Discus fish are extremely social and are one of the few real schooling cichlids. They live in large groups in their native waters, and have a very advanced social behaviour. They need the social interaction to develop their character and behaviour to the fullest. It is therefore wise to keep in mind that you need to purchase a group of discus when starting with this fish, as they are among the higher priced species. A small group of 6-8 same sized specimens is ideal if your aquarium is large enough. Never add young, small size discus into an aquarium with significantly larger adults. The larger Discus will inevitably bully the younger fish, steal their food and leave them starving. Grow smaller discus in a separate tank and only add them to your larger discus when they are close to the same size.
It is a myth that Discus fish are difficult to keep. They are not! But they do require a rigid aquarium cleaning schedule to maintain high quality water standards. You should also consider their special requirements (high temperatures and soft water) when choosing any tank mates. Discus are not very competitive and if you place them in the same aquarium as more assertive fish species, they tend to miss out on food and can starve, or suffer from malnutrition. Although not all hobbyists agree, you should avoid Angelfish, which are greedy eaters and become aggressive very quickly, especially when they reach sexual maturity. Since Discus prefer warm, acidic water, African cichlids are not suitable tank mates. Neither are neon tetras, as they prefer much cooler water. Finally, fast swimming, fin nipping fish like tiger barbs, danios or tinfoil barbs will damage your discus by nipping their fins and will make them very skittish. More docile species are therefore recommended as tank mates. Harlequin Rasbora (Psuedomugil furcatus) do well with discus, as do Corydoras, Plecos and Clown Loaches.
Most of the Discus we encounter today are captive bred and come in a complex array of stunning colour and pattern variants, many of which have very confusing names. To cast light on these distinctions, we wrote a special page on the names and classifications. You’ll find this in the drop down menu under “Knowledge.”
Male and female discus look very similar to one another, and so sexing them is rather difficult. There is no reliable way that I know of to determine their sex. As mentioned earlier, you should have several discus in your tank. Wait until the males and females pair off naturally before you place the pairs in their own breeding tank. It is unlikely if you have 6-8 discus in your tank that you will end up with all males or all females, but it is not impossible – and you will know this when you do not see pairing behaviour.
Discus lay their eggs on a leaf or other surface that they have cleaned prior to spawning. (Discus breeders place breeding cones into the tank for this purpose.)
The eggs hatch within around 48 hours. Before the eggs hatch the parents will guard, fan and clean them. Once the fry hatch they still won’t be free-swimming for another three days. But as soon as they swim free, they begin feeding by eating a mucous secretion off the skin of their parents. You must therefore leave the parents with their fry for at least a few days – a week or two may be even better. After a few days you can then begin to supplement the diet of the fry with newly hatched brine shrimp.
Just a word of warning: Choose your supplier carefully. With the increased breeding of new colour forms, we have also seen increased problems with Discus fry no longer attaching to the parents for feeding. It is suspected that in the wild baby Discus are genetically hard-wired to find the parent by seeing the dark bands on their bodies. In many of the new interbred colour forms these once natural dark bands are either very faint, or have completely disappeared. As a result, the fry seeking the dark bands are ‘lost’, having nothing to spell out ‘parent’ and ‘food’. Only experienced breeders seem to be able to overcome this problem.