The Discus fish is often called the king of the freshwater aquarium, thanks to their gracefulness and colors.
Although they are larger than most tropical fish, the pets are peaceful and can be coupled with other non-aggressive species. Discus fish are not recommended for beginners since they demand stable water parameters.
Appearance
Discus fish are thin and flat-looking hence their name, although some of them can be more round or triangular. They can grow to 8-10 inches, which means that they need a large tank.
The fish have been exceedingly bred to produce many color combinations and patterns. The most common colors are yellow, brown, red, bright blue, and green.
Captive discus fish display brighter hues than the wild varieties. The coloration are distributed in horizontal and vertical stripes that cover the body and the fins.
Wild discus fish have bright red eyes that are prized by some aquarists. In-breeding has, however, resulted in other eye coloration, including albino and yellow. A healthy discus fish will typically have an eye that is proportional to the body in size.
Habitat
The discus fish is a species of the tropical cichlid with wild populations in South America’s Amazon Basin. It is one of the Cichlid species located outside of Africa.
The fish prefer deep and calm rivers stretching across Peru, Colombia, and Brazil, where they seek habitat in the submerged roots and branches in these slow-moving waters.
There are three subspecies of this fish named Green Discus, Brown Discus, and the Blue Discus.
Feeding
In the wild, discus fish eat detritus, plant material, small crustaceans, and worms. This omnivorous diet can be sustained by high-quality flakes, pellets, and granules formulated for discus in the aquarium.
Live and frozen foods make excellent treats, and can even be used to induce spawning. Some aquarists provide their discus with a Beefheart mix, which has not been proven to be harmful to the fish. The diet should be rotated daily to ensure that your discus fish are getting sufficient nutrients.
You can feed your discus fish several times a day, provided you give them meals that they can finish in three minutes. Discus fish are especially sensitive to parasites and bacteria, and they forage at the bottom looking for food, which may expose them to harmful elements.
Water & Tank Requirements
Discus fish need a lot of space because they grow quite large in size. While you can keep one juvenile discus in a five-gallon tank, adults demand twice the volume water of their young ones.
Discus fish are a schooling fish, and you should keep a minimum of six in one tank. You will need a 50-gallon tank for 10 of them or an 80-gallon aquarium for fully-grown discus.
Some aquarists even keep discus fish in a 105-gallon tank if they also include plants.
PH and Temperature
The PH should be between 6 to 7, preferably at 6.5. Discus fish will get stressed when the range is below six or over seven. Tank bred species have survived in higher PH, however, provided there is minimal fluctuation.
The water hardness should be kept at a range of dH – 8dH. The ideal temperature range is 82-88 °F. Such high temperatures reduce the risk of illnesses and deaths in your fish.
Water Conditions
The nitrates and ammonia levels in a tank with discus fish should be at 0ppm at all times. Nitrate levels should also be kept as low as possible, ideally below 20ppm.
Since discus fish are sensitive to water quality, the best practice is doing weekly full-tank cleans and 50% water changes. The substrate should also be vacuumed to get rid of food leftovers.
Some aquarists who keep discus fish recommend the usage of reverse osmosis water. Reverse osmosis is used to filter out impurities out of tap water and maintain an appropriate PH.
The use of reverse osmosis will mostly depend on where the discus has been bred. European discus, for example, will survive in harder water while Asian species prefer soft water.
Discus fish are also adapted to slow-moving waters, which means your tank should have a gentle current to ensure they are comfortable. You should refrain from using heavy filters and opt for calm but effective models. A sponge filter will function well, although you can invest in an under-tank sump to remove solids.
Aquascaping
If you decide on a planted tank, you should look for plants that can tolerate tropical temperatures and an acidic PH.
Some species to consider include Amazon Broadleaf, Java Fern, and Brazilian Pennywort, Anubias, Water Sprite, Jungle Vallisneria, and Bacopa. Such plants will boost the oxygen levels in the aquarium and promote water quality.
Discus do well in soft to medium sediment since they are foragers. Some aquarists prefer to keep discus in bare-bottomed tanks because it is easier to keep pathogens at a minimum.
If you opt to include a substrate, do not use a sharp one, and it should be cleaned regularly.
Discus fish should be exposed to 10 to 12 hours of light. The lights should be dim to mimic the pet’s natural habitats.
Compatibility
Discus fish are more comfortable in large groups, and you can choose to keep them together. As part of a community aquarium, the fish do well shoaling tetras from the same warm Amazon waters like ember tetras, neon tetras, and rummy-nose tetras.
Other compatible species are Bolivian Rams, Neon Hatchet fish, Gouramis, most Corydoras species.
Breeding
Breeding discus fish requires a lot of dedication from the aquarist. The breeding tank should not be very shallow, and a depth of at least 15 inches is often recommended because of their tall shape.
The temperature should be above 82ºF and the PH at 6.5. The water should also be as soft as possible, at an ideal range of 1-4dH. Protein-rich foods are recommended at this point, as are regular water changes.
A spawning cone provides a suitable place for the discus to lay their eggs. A tube of wire placed over the eggs will discourage the parents from eating the eggs. The fry hatch after just three days, and become free swimmers in another three days.
Conclusion
Discus fish can bring stunning colorations and patterns to your aquarium. They may be relatively hard to keep, but their peaceful nature makes it worth it.
You should be very keen on water quality because they are quite sensitive to unstable water parameters.