The Discus fish is a South American Cichlid that belong to the genus Symphysodon, which currently includes three species: The common Discus fish (Symphysodon aequifasciatus), the Heckel Discus fish (Symphysodon discus) and a new species of Discus fish which has been named Symphysodon tarzoo. The Discus fish was first introduced in the 1920′s and is now regarded as one of the most beautiful of all aquarium fish. While they are colorful and attractive, they are quite difficult to care for; nevertheless, their popularity continues to rise.

About Discus

As the name implies, Discus fish have the typical disc-shaped body with full dorsal and anal fins reaching to the tail. The body of an adult Discus fish can reach about 8 to 10 inches in diameter. Originally, due to the environmental diversity of the vast Amazon River basin separate populations developed differential in color and markings. Discus fish breeders have greatly expanded upon this and developed new variations through selective breeding, with the colors and patterns of the Discus fish varying according to the type of species bred, habitat and diet.

Discus fish are widely found in calm parts of small, blackwater rivers, lakes and deep pools throughout the Amazon River basin. The water is usually very clean with little or no pollutants, acidic (6.0-6.5 pH), very soft (0-3 dH) and warm with a temperature of around 77-84°F (25-29°C). They are usually found in small groups around submerged decaying trees, vegetation and aquatic grasses. Discus fish are wild-caught in the Amazon River basin at night by using a strong light to mesmerize the fish, the area is then encircled with netting and slowly drawn closer, with all obstructions such as wood being removed. Some species of Discus fish are now considered endangered in some areas of the Amazon River basin. If you want more information about Discus fish in their natural habitat check out our Wild Discus article.

Discus Fish Book

Discus Fish Tank

Discus fish prefer large tall tanks and I would recommend a minimum of 55 gallons (200L). As for the setup, it entirely depends on the purpose. If for breeding, it is best for the tank to be bare bottom, meaning without any gravel. However, if you want a show tank then it is best to emulate the natural habitat of the Discus fish by provide hiding places, open swimming areas, driftwood, fully planted aquascape and some floating plants (Water Sprite works well) to diffuse the light. A heavily planted tank may also need CO2 injection for the plants to do well; in an upcoming post we’ll be showing you how you can make a CO2 unit yourself out of household items.

Discus fish flourish in water with conditions similar to their natural habitat, however many Discus fish are raised in captivity and tolerant of a higher range of water conditions. While not ideal, most Discus fish can tolerate water with a pH of 5.0-7.5, water hardness of 0-8 dH and temperatures of 77-86°F (25-30°C). Peat moss can be a great way to naturally lower the pH of your aquarium, which I personally use in my planted freshwater Angelfish tank. You can buy some from any garden center for rather cheap, if they happen to not have any you can buy some online, after that put some in mesh bag (cut off panty hose also works) and place it in the compartment where the filter pad sits so water can flow through it. If you would rather not deal with peat moss, blackwater extract contains natural humic and tannic acids that simulates water conditions of the Amazon River basin created by soil, peat moss and decaying vegetation. It makes for better water chemistry, encourages spawning, aids the hatching process and tints the water a light brownish yellow color just like the Amazon River, which is rather cool looking.

Discus fish are delicate and rather intolerant of poor water quality, thus regular partial water changes must be made and maintaining proper filtration at all times is essential in Discus fish care. I do 30% water changes once a week, but I have a fully planted tank, some would argue more or less. I am a huge advocate of the Python water siphon, years ago I had to lug around heavy buckets of water to change the water in my aquariums but this makes it incredibly easy and saves a lot of time as well, it is an amazing investment. Which filter to use for your Discus fish aquarium entirely depends on preference and the setup, personally I use a Penguin 350 for my 55 gallon tank. A fully planted tank once established will aid in this as ammonia, nitrite and nitrate are among the nutrients that plants use, they help the beneficial bacteria keep levels in check and if something happens to your beneficial bacteria there is a buffer present to minimize the problem.

Discus Fish Tank Mates

I believe that a Discus fish aquarium should be entirely geared toward keeping Discus fish, as other species generally do not require the dedication and environment that Discus fish need. The setup, plants and other inhabitants should be carefully chosen for optimal conditions, giving the Discus fish first priority. Discus fish are calm, timid fish who like to be kept in small groups of 5-8 fish, as like other schooling fish they need the security of a school around them. This also helps in reducing stress of acclimating to their new environment. Outside of other Discus fish, what tank mates you choose again entirely depends on the purpose.

If you want a nice display tank, Discus fish feel comfortable with small schooling fish such as characins. When Discus fish see the characins in the open, they are likely to come out sensing that they are safe to swim. I would recommend a large school of characins like Neon Tetras, Cardinal Tetras and Rummy Nose Tetras. It emulates their natural environment and both flourish in the same water conditions. However, you can keep most peaceful slow moving South American fish and Dwarf Cichlids with Discus fish, so long as they don’t dominate or out compete for food and space. Many have had Dwarf Gouramis (including the very underappreciated Sparkling Gourami), as well as Pearl Gouramis with Discus fish. Though I would not recommend the larger more aggressive Blue and Gold Gouramis. Smaller peaceful catfish such as the Corydoras will get along well with Discus fish and do a great job as bottom feeders.

As much as I adore freshwater Angelfish I also would not recommended keeping them with Discus fish as they can grow large and bully the Discus fish, outcompete the Discus for food and carry diseases that Discus fish are particularly prone to catching. It can be done, but usually requires a much larger aquarium and a skilled aquarist. I’ve also known people that have kept Kribensis with Discus fish, but much like freshwater Angelfish they can be aggressive for the Discus fish. They also do better in much more alkaline water than the Discus fish, so I would not recommend it .However, one of my favorite fish is the German Blue Ram (Blue Ram, Ram Cichlid), a beautiful dwarf cichlid that will complement your Discus fish quite well.

For a breeding tank, only Discus fish should be kept and I would strongly recommend against adding anything else. While many love having Plecostomus and other algae eaters, they are notorious for latching onto Discus fish and sucking on their mucus covering, leaving the Discus fish vulnerable to stress and decease. That is not to say that the two have not been successfully kept together, but in my personal experience it has been nothing but issues. For a new Discus fish breeder it is best not to take unneeded risks, even more so with a fish as fragile as the Discus fish.

Discus Fish Diet

Discus fish should be provided a variety of live, dry and frozen foods. Foods formulated specifically for Discus fish are available; I personally use Discus Bio-Gold and Wardley’s Cichlid Advanced Nutrition for a varied diet. Some Discus fish can be very picky eaters and will only take live foods tubifex worms, bloodworms, brine shrimp and beef heart. Try to feed these sparingly to avoid an unbalanced diet. While the frozen foods are safe, buying live food should be cleaned before feeding, as they can often be rather unclean. For example, live tubifex worms can come from polluted waterways and thus must be kept clean or the Discus fish may develop Head and Lateral Line Erosion, also known as Hole in the Head Disease. If you would rather not deal with live food, freeze-dried foods are entirely safe, cheap and easy. Feeding your Discus fish a rich varied diet is not only healthier but it will thrive and bring out much better colors For example, when Discus fish are fed brine shrimp the red tones are enhanced.

Breeding Discus Fish

Before making an attempt at breeding Discus fish you will want to have kept Discus fish for a while. Breeding fish with the exception of perhaps common livebearers is a lot of work and experience with keeping the fish is vital to success. To try and breed a fish as delicate as the Discus fish without having that experience would likely be quite the debacle. Having all that extra work and stress could make it seem as if it were not worth it and ultimately turn you off to breeding Discus fish all together.

Nonetheless, if you plan on breeding Discus fish you will want to have a large group tank which is at least 55 gallons, several smaller tanks for the established pairs and a Baby Brine Shrimp hatchery. A group of 6-8 Discus fish are raised in the group tank and when they reach about 4 inches in diameter (10 cm) pairs will start to form. Distinguishing male and female Discus fish can be quite difficult, adult males may develop a small lump on their foreheads, but this difference is not always reliable. During spawning season the shape of the genital papillae serves as the best differential indicator, round for females and pointed for males, although this difference can also difficult to detect without experience. If a pair begins to peck at the glass they are usually ready to spawn, the pair is then moved into a clean tank and provided a vertical spawning medium, such as a large plastic tube, rock or piece of slate.

The pair will carefully clean the surface, and then the female will lay and tend to the eggs as the male guards the area. The eggs will hatch in two to three days and the pair will move the fry to a different area where they are attached by sticky filaments. After 4-5 days more, the fry attach themselves to the flanks of the parents and feed on a milky secretion produced by gland cells in the parent’s skin. After about 10 days the fry should be removed from the parents or else they may overgraze and damage the parent’s skin. From here the fry are fed live Baby Brine Shrimp, which there are several different ways to do so. There is frozen Baby Brine Shrimp, instant Baby Brine Shrimp and of course hatching your own, which I am a huge advocate of. You can buy a hatchery kit or build your own (which we’ll show you in a future article) using a 2 liter bottle, an air pump, airline tubing, aquarium salt, Brine Shrimp eggs, Brine Shrimp net and Brine Shrimp food. Once the fish grow larger they can eat chopped Tubifex Worms, mini Bloodworms, Brine Shrimp and small flakes. The fry should be fed several times a day and regular water changes are essential for the survival of the young, which will quickly grow and develop the Discus fish shape in 3-4 months.

Discus Books