How Do You Take Care of Discus Fish—How Big of a Tank Do You Need
By Eddie Waithaka @aquariawise
Discus is a genus of cichlids native to the Amazon river basin in South America. The fish are popular with freshwater aquarium owners for their brilliant colors and distinctive shape.
Moreover, these fish are highly social, typically occurring in groups that may number many dozens of individuals, which is unique among cichlids native to the Americas.
For this reason, if you are going to keep discus fish, prepare at least a 50 to 75-gallon aquarium for 5-fully grown adults, which also means, every single discus will require 10 gallons of water space.
Taller fish tanks are ideal because they accommodate the discus body shape best.
Discus fish prefer warm, soft, acidic water with a ph between 6.0 and 7.0, and water hardness of 3 to 9 dGH. The temperature in your tank should remain between 82°F and 86°F.
In the wild, these fish eat a considerable amount of plant matter and detritus but also forage along the bottom looking for worms and small crustaceans.
For this reason, to best care for your discus fish, feed a varied diet of tropical flake foods, color flakes, spirulina foods, tropical granules, algae rounds, or shrimp pellets as staples. Plus occasional treats of frozen or live foods, especially to induce spawning.
Rotate the fishes diet daily and give them only what they can consume in 2 to 3 minutes once or twice a day.
Read on for more insight on how to take care of discus fish in your aquarium. We’ll also dive quite a bit into the diet and feeding, tank and water conditions, and breeding.
Discus Fish Overview
Symphysodon, commonly called discus fish, and sometimes referred to as Pompador fish is a cichlid species endemic to South America.
They inhabit the margins of floodplains, lakes, and rivers in low-lands of the Amazon, but are also common in flooded forests.
Discus occupy both black and white water, though they also occur in clear water habitats. In white water environments, the surface usually contains little suspended material unlike the main sections of the river.
That said, there are three main types of Symphysodon categorized according to their distribution. S. discus is a species restricted to black water habitats but periodically ventures into white waters. S.tarzoo inhabits both black and white water, while S.aequifasciatus occurs in clearwater.
All discus fish species have laterally compressed body shapes, which are more rounded compared to angelfish. It’s this body shape from which their common name ‘discus’ (akin to a discus disc) is derived.
Wild discus fish types are mostly patterned in shades of green, red, brown, and blue. But more brightly colored variants are available in the aquarium fish trade as a result of selective breeding.
The fish typically reach between 4.8 and 6.0 inches in length with males slightly larger than females. Discus fish live for an average of 10 years (lifespan), though it depends on how well you care for the fish.
How Big an Aquarium Do You Need for Discus Fish (Tank Size)?
Both male and female discus fish can reach a maximum of 6 inches in length in under two years. Plus they like being in a shoal, though they are not tight schooling fish like tetras and rainbows.
Therefore, you need at least a 30-gallon fish tank to maintain a pair of discus fish. But to help them feel secure, add 4 to 5 fishes in an aquarium anywhere from 50 to 70 gallons. This way, the fish will form a group and swim together.
Another smart chop is to have 10-gallons of water for every discus fish you keep, meaning a 50-gallon can hold 5-fishes comfortably. However, if you have decorations and plants in the tank, it’s is advisable to go with a larger setup, maybe 70 gallons or more.
Discus Fish Tank Setup
Symphysodon prefer still water and are rarely found in areas where there are strong currents and water activity. Also, they tend to congregate near fallen trees known as galhadas along the shore.
To best maintain them in an aquarium, you, therefore, have to replicate this natural setting in tropical South America.
Tall aquariums are best to accommodate the discus body shape. Plus include large, broadleaf plants and driftwood that is arranged vertically to simulate branches and trees in water.
You can use a few floating plants to provide shade and cover and to make sure the current remains gentle.
The substrate you use should be fine to medium grade gravel. Also, add only soft edge decorations and surfaces as discus often scale the fish tank floor looking for food.
However, some aquarist believe bare-bottom aquariums are better to house discus fish, even though they are not aesthetically pleasing. Having no substrate allows your tank to easily cleaned, and to keep the water quality stable and safe. Which is crucial because discus fish are sensitive to water chemistry than most aquarium fish.
Discus Fish Water Conditions
One of the most common concerns of keeping discus fish is water chemistry because of (as I’ve stated before) the fish’s sensitivity. The fishes are especially troubled by ammonia levels, with the slightest amoung enough to cause a noticeable loss of color and heavy breathing.
Discus fish require warm, soft, acidic water with 0 ppm nitrites, 0 ppm Ammonia and less than 20 ppm nitrate.
A ph between 6.0 and 7.0 and water hardness range of 3 to 8 dGH is recommended, while the temperature range is best when kept between 82°F and 86°F.
Use a heater to maintain proper water temperature because (as you may have noted) discus fish love a pretty warm aquarium environment. Probably more than most tropical freshwater species.
Change at least 50 percent of your aquarium water each week to reduce nitrates and replenish minerals. Plus siphon your aquarium gravel with every water change.
That said, you will find aquarists who claim to change their discus aquarium water 2 to 3 times a day (or week). Which is technically overkill but Ok if you have that much time and dedication.
Even so, reverse osmosis (RO) water is recommended as it takes minerals and other elements out of the water and makes it pristine enough for keeping discus.
You can use soft tap water as well, especially if you add extra softners.But don’t forget to treat your tap water with a conditioner before refilling your aquarium.
Using blackwater is also good as it contains natural humic and tannic acids that simulate the water condition found in the Amazon regions of South America.
Lastly, when purchasing your discus, always ask about the water chemistry they were raised in to keep them from dying once they are acclimated into a new environment.
Discus Fish Filtration
Contrary to common belief, discus fish don’t need much of a different filter than other freshwater aquarium fish. But remember to use a unit that causes minimal water movement.
Lower to medium flow rate units are ideal because these fish are not good swimmers and can’t handle strong currents. Over and above being native to still water habitats.
Even so, a filter with an efficient filtration media (particularly biological filtration) is paramount given the fish sensitivity.
Ideally, use a hang-on-back or canister unit with multi filtration and an adjustable flow rate. You want at least a 3-stage filter that will engage the 3-main types of filtration (biological, mechanical, chemical).
Plus use a multistage filter rated for twice your aquarium capacity. However, if you must, you can forego the chemical filtration but not mechanical and especially not the biological filtration.
Adding the right plants can also help with the waste and aid your filter clean the tank.
What Fish Can You Keep with Discus (Tankmates)?
Usually, discus fish get along with many fish species as long as they share the same water requirements.
That said, you will want to take your discus as the starting point when choosing tankmates for them instead of making them conform to other fish.
Choose the companions based on temperature, water values, tank size, and biotopes. Because of this, most fish you can put with discus will be native to South America, especially within the Amazon basin.
Most corys make good discus tankmates (temperature-wise), though some species like the Sterba’s cory do better because they are bigger.
Moreover, corys are the perfect candidates because they occupy different water levels with discus and perform crucial cleaning duties in the aquarium.
Another group of fish that make good discus companions is the tetras, with cardinal and rummy nose tetras particularly suitable. The two species are large enough to avoid falling prey to hungry discus, and their friendly temperament ensures stressless cohabitation.
Instead of tetras, you can also add golden pencil fish with your discus. They are peaceful and grow large enough to avoid being eaten.
A variety of bottom-dwelling plecos and catfish also do well with discus and are good at cleaning like the corys. However, avoid larger species like clown loaches because they’ll scare your discus during feeding.
A simple rule of thumb is to avoid bottom-dwellers that grow to more than 5 inches in length.
The unusual shaped fish of the hatchet family make unique discus companions and have been kept with them for long. Like the corys, these fish make good tankmates because they inhabit different water levels but can live in the same water conditions as discus.
The neon and marbled hatchet fish are particularly good choices from their family.
If you are looking for colorful tankmates to compliment your discus, consider housing them with German blue rams which are amazingly colored and peaceful.
However, it’s important to know that rams become feisty when breeding. So if you choose to maintain them with your discus, add plenty of plant and a few flower pots and caves to break the direct line of sight.
Lastly, consider inverts like assassin or Malaysian trumpet snails.
This is the full list of good discus fish tankmates.
- Rummynose tetra
- Serpea tetra
- Gold tetra
- Black emperor tetra
- Congo tetra
- Penguin tetra
- Glowlight tetra
- Malaysian trumpet snail
- Assasin snail
- Harlequin rasbora
- dwarf gourami
- Honey gourami
- Siamese algae eater
- Pencil fish
- Gold nugget pleco
- Corydoras Agassizi
- Panda cory
- Emerald green cory
- Sterba’s cory
- Julii cory
- Long finned peppered cory
- Bristlenose pleco
- Long finned red white cloud
- Peacock gudgeon
- Rainbow shark
- Blue ram cichlid
- Bolivian ram
- Golden ram
- Neon hatchetfish
- Marbled hatchetfish
Discus Fish Care (Diet, Food, Feeding)
In the wild, discus fish typically feed on small worms, crustaceans, plant matter, insects, and detritus that get flushed out of the surrounding forest by rain.
They are not picky eaters, but the preferred food varies with the species. For instance, blue discus fish (Symphysodon aequifasciatus) dine on lots of bugs and bug larvae. While red or Heckel discus fish (Symphysodon discus) consume lots of plants, crustaceans and worms.
All in all, discus are omnivores and will eat most fish food in an aquarium. However, using the right combination of live, frozen, and flake food is key to maintaining healthy, well-fed fish.
Feed your mature discus fish a diet that consists of about 35 to 45 percent protein. While younger and newly hatched fry should eat a diet consisting of up to 50 percent protein to accelerate their growth.
Vitamins are equally important because they provide the necessary building blocks for the proper functioning of the fish’s immune, reproductive, and digestive system.
Good source of vitamins for discus fish are crustaceans, vegetable, and algae.
Whereas good protein sources include bloodworms, earthworms, brine shrimp, white worms, and mosquito larvae. Spirulina will help develop your fish’s color.
It is also not unusual to find aquarists feeding discus fish beef heart albeit being scarcely available. Usually, you must contact your local butcher days in advance to order for beef heart.
Moreover, discus should be fed beef heart with a lot of caution as it can lead to digestive issues and other related illnesses.
Discus fish will sometimes consume flake foods but don’t make them the focus of their diet like other tropical fish. They’ll also eat pellets.
When feeding you fish, try to avoid overfeeding them, a mistake most beginners make. Giving discus too much food will lead to obesity along with a whole list of health issues and a dirty aquarium.
A good rule of thumb is to feed your discus fish about 3 percent of their body weight per feeding. Alternatively, offer them what they can consume in 2 to 3 minutes.
Plus, if uneaten food remains in the tank for more than 15 minutes, remove it to maintain proper water conditions. And consider feeding them lesser food or changing the diet.
One last thing, live food should be administered as slumps directly in the tank. While flake and freeze-dried food work better when sprinkled on the surface of the water.
Discus Fish Breeding
Discus are not easy fish to care for, neither are they easy to breed. Which means you may not attain a high fry survival rate like with other freshwater species that are easier to breed.
If you decide to go ahead and breed your discus, start by creating an environment that will encourage spawning.
Usually, the settings will depend on whether you are going to raise your fry together with the parents or in separate aquariums.
Fry raised in the same aquarium as their parents are easier to care for since they feed from the parent’s skin albeit being at risk of cannibalism and diseases.
On the flip side, fry raised in a separate tank are safe from cannibalism and infections. However, they are difficult to care for because you’ll need a specialized replacement for the parent’s nutrients.
Even so, these fish are not outrightly cannibalistic, and only young, unexperienced parents will eat their young ones.
How to Encourage Your Discus Fish to Breed
There is no clear sexual dimorphism in discus fish, which means there is no sure way to visually tell your fish apart.
For this reason, the first step to encourage your fish to breed keeping several fishes in your aquarium to increase the odds of having both male and female discus.
Keep them in a spacious-tank and make sure you measure and adjust the water for nitrites, ammonia, and nitrates. Also, test other water conditions and adjust them carefully to appropriate levels.
Overall, the temperature in your aquarium should be 82°F or higher and the ph test results be around 6.5 and not raise above 7.0.
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Have fun with your lady betta.