Care Guide for Discus Fish – The King of the Aquarium

Discus fish are one of the most beautiful freshwater fish in the hobby, known for their spectacular colors and large, circular shape. Discus fish are notoriously difficult to maintain. Many forums recommend strict water changes, such as 100% every day, which is something many Internet forums encourage. In reality, only a small percentage of people are able to follow those rules, and the rest of the world uses more low maintenance methods. We’ve spent many years keeping discus personally at home, caring for them in our fish store, and helping customers be successful with them. This care guide is based on our experience and provides useful tips and practical advice for anyone starting a discus tank.

What Is the Ideal Temperature for Discus Fish?

The easiest trick for keeping happy discus is to raise the water temperature. We recommend that the water temperature be between 85 and 86°F. This is because discus farms that we source them from keep their water at these temperatures. If we force them to cool off, it can cause discomfort. When the heat is kept high, your discus become more active, their metabolisms run well, they grow faster, and they show off better colors. You must be prepared to change your fish keeping habits if you want discus to thrive.

Other environmental conditions to consider include pH and water hardness. This is a controversial issue as many people are very concerned about the recommended pH. We have found that both wild-caught discus and captive-bred discus perform well at pH levels between 6.8 to 7.6. The same thing applies with water hardness; discus are usually fine with soft to medium hardness. While we haven’t had the pleasure of keeping German-bred discus yet to this day, it is known that they can tolerate higher pH and more hard water. If you’re focused on breeding and raising discus fry, you need much lower pH and water hardness, but if you’re simply keeping them for enjoyment, these two water parameters aren’t as important.

Although aquarium plants and tank mates are possible for discus aquariums, they must be capable of handling the required hot water temperatures.

What size tank do you need for discus?

Bigger is always better, so we personally recommend a 75-gallon aquarium or larger. Although a 55-gallon tank can be used, you will have to make frequent water changes. These fish grow up to 5 to 7 inches in size if they are treated properly. Heating up the tank can increase their metabolism, which means that you need to feed them more. (That’s why people recommend doing all those frequent water changes.)

We get asked a lot by customers if we can keep one discus. Dogs are considered pack animals. However, many people only keep one dog and leave the rest at home. It’s not ideal, but it’s doable. The same thing applies with discus.

However, they are schooling fish by nature and are much happier when surrounded by a large group of their own kind. As a type, cichlids can bully each other, so make sure you have enough. In order to mitigate this territorial aggression, buy 10 to 12 juveniles all at the same time for your 75-gallon tank. (You want them to be approximately the same size so that no one gets outcompeted for food.) As they get bigger, you’ll be able to identify the rowdy males and rehome them back to the fish store. You will eventually have a peaceful group of six adult discus, mostly females, with maybe one or two males.

As for tank setup, you can put them in a planted tank, but make sure to find plants that can tolerate high temperatures, such as anubias, java fern, bacopa, sword plants, and micro swords. Air stones are also recommended as the higher water temperatures can reduce the oxygen level. An air stone can be used to reduce the chance of low oxygen levels in summer, when temperatures are higher than usual.

Start by creating a larger group of juvenile discus, then you can remove the more aggressive discus over time.

Do Discus Really Need Daily Water Changes?

It depends. It all depends. Therefore, the amount and frequency of water changes really varies for every aquarium. Several considerations include how large your tank is, how many fish you have, how much you feed them, and how much biological filtration (e.g., beneficial bacteria and live plants) you have. We recommend that the nitrate level be kept below 40 ppm in planted tanks, and less than 20 ppm in non-planted tanks.

Get an aquarium water test kit to determine how often water changes are needed for your aquarium. You can also download our free infographic which guides you through the process step-by-step.

What fish can you keep with Discus?

Two requirements must be met for tank mates to meet: they must have the ability to survive in high temperatures, and they must not outcompete discus when it comes time to eat. Discus are slow feeders so they will lose their race if they are paired with fast, bullet-shaped fish like barbs or huge schools of Tetras. Even hot water fish like angelfish, clown loaches, and German bluerams can be too fast to them.

Consider starting with a discus-only tank, where they will be the main fish. Once they’re eating well, add Sterbai Cory catfish, cardinal Tetras, and a bristlenose pleco. However, avoid getting too many tank mates, or else the discus may lose out on nutrition.

Cardinal and Tetras make a great tank mate for discus tanks. However, they can’t outcompete the discus in food competition.

What’s the Best Food to Eat for Discus Fish?

People feed discus animals food that is too large, but they don’t realize that their mouths are very small. Therefore, if you see them eating the food, spitting it out, and then mouthing it again, you may have a problem with the size of the food.

Frozen bloodworms are great because their skinny shape is perfect for slurping up, but discus can get addicted to them quite easily. To ensure they get all the nutrients they require, make sure you give them plenty of small food items. Pre-prepared foods such as Hikari Vibra Bites and Sera Discus Granules or Tetra Discus Granules have been a good choice. Other suggestions include frozen or live brine shrimp, live or freeze-dried blackworms, and live microworms.

Why are Discus Fish so Expensive

This was something we mentioned previously. Tank conditions are essential for raising fry and breeding them. It’s very time- and labor-intensive work, especially since discus take longer to reach full adult size compared to other cheaper fish like guppies. You can buy discus from local breeders, fish stores, or even online, but if you’ve never kept discus before, our best advice is to stay away from the price extremes. In other words, don’t buy the cheapest ones that may have quality issues, and don’t buy the $300 adults that may die from your lack of experience. Just remember to purchase a group of them that are all the same size to minimize bullying.

Keeping discus for entertainment is easier than caring for high-maintenance discus fry.

How Do You Keep Discus Fish Happy?

The main takeaway from this care guide is to

reduce stress

. You should raise the heat, maintain the water temperature, and give them proper nutrition. Don’t let kids tap on the glass, and limit the amount of traffic near their tank. You should also avoid placing their aquarium next to a TV that emits loud noises or flashing lights. You can do anything you can to make these timid creatures feel secure. This will help improve their health and life quality.

Don’t forget about your stress levels! Many discus beginners spend too much time worrying about whether they will accidentally damage their discus. Instead of enjoying their magnificent beauty and relaxing, many people don’t realize how important it is to reduce their stress. With these simple guidelines, you’re on your way to having a successful, enjoyable discus tank for many years to come.

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