Discus fish are often considered to be the mighty, holy grail of the cichlid community. They are gorgeous fish with a very unique body shape. And they have been bred to display an astounding array of color variations on par with koi fish and flowerhorn cichlids.
Discus fish used to be extremely difficult to keep because the majority were wild-caught or a few generations removed. But now they have been domesticated and can be kept by intermediate-level aquarium hobbyists. Even a dedicated beginner who has done their research has a good chance at keeping this majestic beauty alive.
So how does one care for discus fish, some of the most beautiful freshwater fish in the world? In this guide, we will be taking a deep dive into the world of discus fish care, including water quality, feeding, and breeding.
In This Article
- About the Discus Fish
- Discus Cichlid Care
- Good Discus Tank Mates
- Setting Up a Discus Tank
- Plants and Discus
- Breeding Discus
- In Conclusion
- More Frequently Asked Questions about Discus Fish
About the Discus Fish
The term “Discus” came about due to the flat, circular “disk” shape of this fish. Just like other cichlids, Discus are extremely intelligent and personable. But sometimes other cichlids have too much personality and cause problems with their tank mates and aquarium decorations. Fortunately, discus are very peaceful and non-destructive towards plants and decorations.
There are three or two species, depending on which text you consult. Current classifications list three species of discus but the majority in the hobby are all Symphysodon aequifasciatus: the Blue or Common Discus. The other two discus fish types are much rarer in the hobby and are favorites of specialists since they are just as sensitive as any other wild-caught discus fish. Selective breeding also has not brought out bright colors in these other species..For now.
- Scientific Name: Symphysodon aequifasciatus, S. discus, S. tarzoo
- Size: 5-8”
- Origin: Amazon River Basin in South America
- pH: 4.0-7.6
- Temperature: 82-88°F
- Tank Size: 55+ gallons
- Temperament: Shy, peaceful fish
- Wild-Type Colors and Patterns: Green discus, Brown discus, Heckel discus
- Captive raised Colors and Patterns: Solid red discus, Albino platinum discus, Blue Discus, Pidgeon blood discus, and many more
Adult Discus Temperament
Despite being a cichlid, Discus are normally very timid and calm, which is the opposite of the aggressive nature that most cichlids display. You may still experience the odd aggressive Discus, but this occurrence is very rare and usually directed towards each other and not their tank mates.
Discus are a schooling fish and need to be kept with at least five friends. In fact, they do better with even more companions. But six discus per home aquarium is a good minimum.
They also appreciate having plenty of hiding places. Discus don’t need to disappear entirely but they do need something to hide behind. Items like live plants and driftwood do make cleaning the tank difficult. But when your discus know they have cover nearby they will be bolder about remaining out in the open.
That said, it is not unusual for them to act extremely skittish and hide in the corners of the tank for the first few days that they are introduced to their new home. It takes discus some time to settle into a new aquarium.
Lastly, remember that all discus crave stability. While they do require large and frequent water changes, they do not handle changing decor or tanks very well and will become skittish until they settle back into their niche as the king of the aquarium.
Discus Natural Habitat
The Discus Cichlid comes from the Amazon River in South America. They inhabit very soft and acidic water, which initially made them difficult to keep in the average aquarium.
At first, they would only live in blackwater aquariums (water heavy in tannins) and water with a very low pH. Since most tap water is very alkaline (high pH) and rich in minerals it made keeping discus very difficult for decades.
The good news for you is that this is no longer true! Captive-bred discus still prefer a lower pH. However, they can still thrive in water with a pH up to 7.6 and they will survive higher levels still. Just know that you will see better colors and have a much better chance of breeding them in water conditions more to their liking.
Their natural habitat also tends to have a great deal of wood in it, mainly from fallen trees and branches, so they do appreciate having large pieces of driftwood in their environment.
Common Discus Illnesses
Since Discus require such high temperatures in home aquariums, some illnesses and parasites, such as Ich, do not afflict Discus as commonly as other fish.
That being said, there are still some serious illnesses that Discus are prone to, and they can still be afflicted by ones that prefer lower temperatures, including Ich. That said, if you do see ich in discus it may be a sign that your temperatures aren’t high enough.
Unfortunately, these same high temperatures leave Discus open to fast-breeding strains of bacterial infections like cotton wool disease, which normally occur on the skin and fins.
Discus are also prone to developing Hole in the Head disease and are weak to internal and external parasitic infections, especially gill flukes.
Discus Cichlid Care
Discus cichlid care is a little more involved compared to other cichlids. So let’s take some time to break down the basic requirements for keeping Discus.
Are Discus Fish Sensitive to Ammonia?
All fish are sensitive to ammonia, nitrite, and nitrate, but the Discus cichlid is more sensitive than the average fish.
Their sensitivity is another factor that initially made them difficult to keep, as their natural habitat does not have any ammonia, nitrite, or nitrate. Therefore, even very low levels of the safest compound (nitrates) will cause them significant stress. That means you need to remain vigilant and quick to perform water changes on a regular schedule.
Live plants are always recommended for discus tanks. They do provide cover and look beautiful. However live plants also absorb nitrogenous waste products as fertilizer, acting as living filters for your fish tank and improving the overall water quality.
What do Discus Fish Eat?
Despite their cute faces and small mouths, the Discus is a carnivorous fish. They primarily prey upon aquatic insects, fish, and crustaceans in the wild.
In captivity, the best food is high-protein items like beef heart. This can be mixed with other ingredients and turned into a staple food for them. Bloodworms (frozen or live) are also good supplemental food for them. And don’t forget about other sources of high-protein food, including brine shrimp, shrimp pellets, tubifex worms, and daphnia.
The issue with them being carnivores is that they need a rich and expensive diet, which turns into a lot of waste. Carnivorous fish create loads of ammonia, which can easily foul the water quality.
This, coupled with their sensitive nature, forces the owner to do very large water changes on a frequent basis.
Receiving Shipped Discus
Since Discus are still regarded as a “specialty” fish, you might be hard-pressed to find some in local stores. They are sensitive and more of a specialist item whereas local stores tend to want fish that are always popular and sell readily.
And even if you do find some in local stores, they are often low quality and very expensive. It is usually much cheaper to buy a group of Discus online than it is to buy a group in-store.
Most fish you receive through the mail can be added directly to the tank, no acclimation is needed besides the temperature (in fact, it is often discouraged to acclimate Discus for too long due to the ammonia buildup in the bag).
That said, Discus are often shipped with materials like zeolite resins that reduces ammonia in the bag. Once they arrive a quick drip acclimation between 5-20 minutes in length is helpful.
If they are shipped without any material in their bag, float the bag, pour the Discus into a net (do not get the bag water in the aquarium), and then plop it in its new home.
There is one thing that you may experience that is unique to Discus: flat fish. By this, I mean fish laying on their side at the bottom of the aquarium. Normally, this would mean the fish is sick or dying, but with Discus, it can mean something else.
In the bags, the water pressure is very low. Once transferred to an aquarium, the water pressure becomes much stronger, and with the sensitive Discus, this often pushes them down on their side.
If you experience this, drain the tank to only a few inches of water, and they will right themselves very quickly.
Good Discus Tank Mates
Even though six captive-bred Discus often make a tank appear fully stocked, you can keep your Discus with several other species of fish. You simply need to choose their tank mates carefully since they are as peaceful as they are sensitive.
Potential Issues with Other Fish
Discus are shy and need to be kept at much higher temperatures than most other fish. Keeping fish at the wrong temperature often results in disease and a shortened life span.
Build your community aquarium around the Discus, not around the other fish. Your first priority needs to be the Discus because of their sensitive nature.
In addition, they can only be kept with peaceful fish, or else they will hide constantly.
Suitable Discus Fish Tank Mates
The best tank mates for Discus are schooling fish that are smaller and entirely peaceful.
If schooling fish are out and about, that signals to the Discus that the area is safe. In addition, schooling fish tend to stay with their own kind and will not bother your Discus.
For a more comprehensive guide on proper tank mates, check out our article on 9 Perfect Discus Tank Mates.
A shorter list of potential candidates includes Sterbai Cory Catfish, Cardinal Tetras, Red Eye Tetras, Neon Tetras, Hatchetfish, some Plecostomus Catfish, Clown Loaches, Glowlight tetras, and German Ram Cichlids.
Setting Up a Discus Tank
While Discus do need a good bit of care, setting up a tank is very easy.
Equipment for a Discus Tank
Since Discus are so sensitive and require large and regular water changes, you will need a reliable water changing system.
The easiest way to carry out these water changes is with a Python water changing system.
This is a hose and gravel siphon that attaches to a sink faucet with an adaptor. It is easy to both drain water and fill the tank back up using the sink.
There are some DIY alternatives, but they can be prone to leaking, unlike the real thing.
When adding water back to the aquarium, this water is entirely chlorinated, so you should first turn off the filters to prevent loss of the beneficial bacteria.
When adding the water into the tank, dose the entire volume of the tank with a water conditioner that is safe to overdose, such as Seachem Prime. Be sure to unplug your heater and filter(s) when doing water changes.
In addition to the water changing system, you need an adjustable heater capable of handling temperatures between 82-88 degrees, a powerful filter, and of course, a tank.
A 55 or 60 gallon is a good place to start for a school of Discus, but bigger is always better.
Decorations and substrate are not necessary for them, nor are plants. You will also need a quality light in order to admire your fish properly.
For the filtration, canister filters are often best for Discus, as they have the most area for beneficial bacteria to grow and have a strong flow.
Sponge filters are often not powerful enough for Discus and get clogged easily, and Hang on Back filters can work, but tend to lack enough flow.
The recommended water change schedule for Discus ranges from 50% daily to 80% once a week to biweekly. The best way to determine when you need to change your water is to test your nitrates. Discus do not handle high levels of nitrates, and you should never let them get over 20ppm, with nitrates between 0ppm and 10ppm being ideal.
Even if you have 0ppm nitrates, you need to change the water at least every other week to maintain good tank conditions. Water changes also help replenish essential minerals that fish need.
Choosing a Substrate
Any particular substrate is not important for Discus, but it does help with the aesthetic of the tank. A bare bottom tank is very easy to clean, which is a big plus when keeping Discus, but it is plain, and the waste stands out.
One of the easiest alternatives to a bare bottom tank is a tile or rock bottomed tank. These are tanks that do have a bare bottom but are instead entirely or partially covered by tiles and rocks. This keeps the ease of cleaning associated with bare bottom tanks but brings a better aesthetic to the aquarium.
Sand and gravel are also acceptable, but they are much more difficult to manage. If you plan on keeping a lot of plants, substrates made for plant growth can work, but there are other issues associated with plants, which we will discuss in the next section.
Plants and Discus
Beautiful plants plus a beautiful fish equals the perfect tank, right? Plants also act as living filters, soaking up ammonia and other pollutants.
Plants look amazing in Discus tanks, but there are some issues associated with them. The main issue relates to cleaning the tank. Plants tend to trap debris and waste in their leaves or around their roots.
Since you may not be able to get rid of this waste, there is a chance that you will encounter a nitrate problem. On the flip side, if you have enough plants, they will take in most of the nitrates in the tank.
The bright coloration of Discus makes them a perfect fish in a planted tank. The plants will make cleaning the tank much more difficult, as a siphon will not be able to reach within the plants or underneath them. The easiest way to clean the plants is with a turkey baster.
Adding Live Plants
Stem plants and floating plants are the best plants to remove nitrates. Anacharis in particular is very good at removing nitrogen compounds. Amazon swords are common in Discus tanks due to their large, bushy appearance and deep green coloration that make the Discus pop. Here is a list of low light plants that do not require a huge amount of nutrients and care:
- Anacharis (Brazilian Water Weed)
- Scarlet Temple
- Banana Plants
- Red Root Floaters
- Java Fern
- Java Moss
- Christmas Moss
- Dwarf Sag
- Amazon Sword
The main issue with plants is finding species that tolerate or thrive in the same hot water that discus require. I’ve put together a list here of 10 Awesome Plants for Discus Tanks.
Cycling a Discus Tank
The term “cycling” a tank refers to the nitrogen cycle. The nitrogen cycle is arguably the most important part of keeping fish, as they will suffer and die if the owner does not have proper knowledge of this process.
If one attempts to place a Discus in an uncycled tank, they will always die. Some fish can survive a “fish-in” cycle, but a Discus is not one of these. Any level of ammonia or nitrite will result in their death.
Nitrate is less of an issue and generally only causes long-term damage, unless you are keeping sensitive fish like Discus. Levels below 20ppm are safe for sensitive fish, but even 0.25ppm of ammonia or nitrite is toxic and can be lethal to Discus.
There are two reasons that ammonia and nitrite are incredibly harmful to Discus: the first is that Discus are extremely sensitive, but the second is that these compounds increase in toxicity as the temperature increases. Therefore, the high temperature that Discus require makes these compounds lethal.
While breeding any fish is rewarding, breeding Discus and raising fry successfully is one of the greatest possible accomplishments in the fish hobby.
Determining Discus Gender
Determining the gender of this cichlid is very similar to determining the gender of angelfish; you cannot determine the gender by looking at the fish. You must see the breeding tubes, which only drop during spawning, in order to determine the sex of your fish.
Some claim that a Discus can be sexed by the shape of its tail fin (rounded for females, pointed for males) after they reach a size of four inches, but this method is often inaccurate. The only way to be entirely sure of your fish’s gender is by observing the spawning.
The breeding tube of the female is wider and has a blunt end, while the male’s breeding tube is thinner and has a pointed end. You may also see your fish spawn in a community tank, and since they tend to stay near their eggs and defend them, you should be able to determine which fish spawned by simple observation.
Setting Up a Spawning Tank
A 29 gallon is a good place to start, but you will need larger tanks to raise the fry. The sides of the tank should be painted either white or blue, as the discus fry will have difficulty finding the parents otherwise, and/or the parents can become too stressed to spawn. Three sides of the tank should be painted; all but the front panel.
The tank should be entirely bare except for a filter. A hang-on back or canister filter should be used to keep the water pristine. Keep either a fine sponge or 100% nylon stocking over the intake to prevent babies from being sucked up and ground up in the impeller. If the filter is not an established filter and fully cycled, you will lose the fry and the breeders.
You should also have a heater and something for them to spawn on, often a spawning cone made of terra cotta. If the tank has a sump, it is best to place the heater there. If the Discus use the heater as a spawning area, the eggs may die from the excessive heat.
How to Spawn Discus
Before spawning, you will see the Discus pecking at and cleaning the area they want to use to lay their eggs. Once they decide it is clean enough, the female will lay a row of eggs, and the male will come in behind her and fertilize them.
They will continue this process until the female has laid all the eggs, which can take several hours. Do your best not to disturb them during this process, as they will eat the eggs if stressed.
Caring for Discus Fry
The babies feed off of the parents’ slime coat. You need to ensure that the parents stay with the fry and that you feed the parents well. If you do not, they will become weak from the fry constantly grazing off of them and the fry will not have enough food.
When the fry are still in the wriggler stage (not quite hatched, but you will see wiggling tails), the parents tend to move the babies around quite a lot. Don’t immediately assume they have eaten the fry until you have investigated every area of the tank.
Baby brine shrimp is a great first food for these fry; expect to need multiple hatcheries running at once. You can also add beef heart and other foods, such as bloodworms, to a blender and process it finely. Then you can begin to feed those before they outgrow the brine shrimp. They should take to crushed flake food just a couple of weeks after hatching, which is much sooner than most fry.
If all goes well, they will be sellable size (2”) once they reach 12-16 weeks of age. As they grow, they require very large daily water changes, often upwards of 60%. They produce a massive amount of waste and are more sensitive than the adults.
Selling Discus for Profit
When you start breeding Discus, you may think that there is continuous profit in doing so, considering most Discus sell for $20-150, depending on the size and type. However, most people who keep fish tanks are not interested in spending over $40 on a single fish, especially one that requires at least five more companions.
Discus have a massive number of babies, often over 100. Since Discus are normally only bought by specialized hobbyists, you will quickly run out of potential buyers for the strain you are breeding. After just one spawn, the market will be saturated, and you will not profit from a second spawn.
The amount of care and expense of food that young Discus require means that you will be earning a minimum profit. If you worked an average job, you would likely make more money. That being said, breeding fish, especially fish as picky as Discus, is rewarding, fun, and you should be able to make some profit.
The best way to maximize your profit is to buy a breeding pair (or use a pair you have), breed them, and sell the fry. Next, since that strain will be saturated for a few months to a year, you should either retire the pair for that time period or sell them. A proven pair often sells for $300-500, depending on the age and strain.
Discus are a wonderful fish to keep, and some of the largest schooling fish available for aquariums. Their vibrant color will light up every aquarium, and their peaceful nature is perfect for a community aquarium.
Caring for the king of the aquarium world is a challenge not every fish tank keeper is up to. Discus ask a lot from you, from the size tank required to specialized water conditions. But few fish are as enjoyable to feed, watch, and if you are very lucky, breed for yourself. If you’ve kept discus and have tips of your own to offer, I’d love to hear from you in the comments section below.
More Frequently Asked Questions about Discus Fish
Is Discus Fish Hard to Keep?
Discus can be considered intermediate-level fish in terms of difficulty. Not as easy as most commonly available community fish but they are easier to care for than their wild-caught descendants.
How Many Discus Fish Should Be Kept Together?
At a minimum, you want to keep at least six discus together. They are schooling fish and are highly social with each other.
What is the Minimum Tank Size for Discus Fish?
Since discus grow to be between 5 and 8 inches long and live in groups you want at least 55 gallons of space for a small group of them to live together.
Are Discus Fish Schooling Fish?
Discus fish do school and live with each other. And despite being cichlids they are very peaceful towards each other. You can also keep them with other peaceful schooling fish, including cardinal tetras and corydoras.