Why do Discus Fish Keep Dying? 5 Reasons & Remedies

People absolutely love to keep Discus fish at home. They find their unique patterns and beautiful colors irresistible, making it a must to buy a few of them at the pet shop. However, these little beauties can be rather demanding.

Many beginner fish keepers need to say good bye to their Discus before they figure out their needs.

If you have set yourself the goal to by some of them, I recommend you to read this article first. It is important to be familiar with the various factors that contribute to the well-being of this species.

Instead of going through various forums and knowledge bases, you just need to keep reading here. Besides sharing some useful tricks and tips with you, I am going to explain the most common reasons why Discus fish die in a home aquarium.

Reasons Why Discus Fish Die

There are various reasons why the health of your Discus can get worse and worse to the point of no return. The interesting thing about them is that they apply to any other fish you can keep at home. You just need to get better at understanding the basic needs of any aquarium fish.

Doing some research online always helps. It helps even more to read a summarized, well-rounded article on the topic that solves your problems once and for all. In the end, it always comes down to water quality, parameters, tank mates, diet and diseases lurking in the tank.

No matter which species you keep in your aquarium, the rule of thumb is to set up a clean, comfortable environment.

Some fish are more sensitive while others are more forgiving. Nevertheless, you need to be precise and spend some time on satisfying the basic needs of your precious Discus day by day.

1. Poor Water Quality

First off, you need to de-chlorinate the water before you put your fish in the aquarium. This is because tap water is not ideal and it has to be treated with formulas so that your pets can thrive in it. Secondly, you need to change the water on a regular basis.

Tank maintenance is key especially with such a sensitive species as the Discus. This includes keeping the nitrite levels low by properly filtering the water and changing it. Another important practice is to remove leftover foods, for which the best tool is the gravel vacuum.

About 20 percent of the water has to be changed every week. Testing the water for contaminants and general quality always helps when it comes to fish care.

2. Low Water Temperature

The water temperature has to be set precisely for your Discus fish. It can really stress them out if it is below the recommended minimum of 82 degrees Fahrenheit. The lower the temperature, the higher the chance that your fish is going to get sick and eventually die.

The solution to this problem is simple. You need to buy a heater and install it so that you don’t need to worry about the temperature ever again. This is one of those things that Discus are really sensitive to. They get incredibly stressed once the temperature changes to the worse.

In general, most fish species are rather sensitive to sudden temperature changes. It makes their immune system weaker and then it won’t take long until they get dangerously sick.

3. Overcrowded Tank

Providing enough space for your Discus fish to swim around and feel comfortable is just as important as picking the right tank mates. They need enough space to thrive and if there are too many other fish that surround them, they can feel stressed.

Not to mention that they have a peaceful temperament. This also means that you shouldn’t put them in the same tank with aggressive or territorial species. Discus have to feel unthreatened and undisturbed by their tank mates.

Set up an aquarium where they can have their own private space and even hide if they want to. You can overcrowd the tank with peaceful fish as well. In that case, they generate a lot of waste which will rapidly contaminate the water.

Before you know it, diseases will spread and your fishes will start dying.

4. Overfeeding

Aim to keep your fish on a balanced diet and make sure not to over feed them. A Discus really needs only the amount of food he can eat within 5 minutes. Anything more than that can cause digestive problems.

Overfeeding also leads to the accumulation of leftover foods in the aquarium. It will contaminate the water over time, making it so dirty that it ruins the water parameters.

If you don’t remove leftover foods in time, they can clog up the filter and shorten the life of your filter media.

If you don’t want health issues to manifest themselves, make sure to remove excess foods. This needs to be done within couple hours after your Discus have finished eating.

5. Diseases or Parasites

Your Discus are going to be the most vulnerable to diseases and parasites when their immune system is weak. I have already talked about the most factors that can weaken their immune system.

Dirty water, overcrowding, overfeeding and inaccurate water parameters are all potential health dangers.

Ensuring a healthy environment for your precious pets is key. Diseases and parasites simply can’t spread in a well-maintained, clean aquarium.

Even if they do, there is a slim chance that your fishes are going to be affected because they have a strong enough immune system.

This is especially true if you keep them on a healthy, balanced diet. Provide them with enough vitamins, fibers, minerals and proteins so that they can defend themselves against potential health risks. Keep in mind that some of the diseases and parasites can be fatal.

How to Keep Your Discus Fish Healthy?

There are daily maintenance practices that are easy to forget, yet they are crucial for keeping your Discus fish healthy. If you find it hard to feed them in time or perform water changes, then set up reminders or ask someone else in the house to do these chores.

Things like removing leftover foods or changing the filter media are just as important. You can also notice when the aquarium gets dirty enough so that you have to thoroughly clean it. This is something that has to be done from time to time.

Putting your Discus fish into a separate container full of aquarium water for a couple of hours is something they can easily tolerate. In the meanwhile, you can remove everything from the aquarium and clean it thoroughly including all the accessories.

Do Discus Fish Play Dead?

If you notice any suspicious activity from your Discus fish, it is usually because they don’t feel well. They are not going to play dead laying on the ground or swimming in an unusual manner for no reason. Sloppy movement, loss of appetite and leisons on the body are all potential signs of illness.

In these cases, it is better to assume that your fish is sick than to say he is just lazy or having a bad day.


Discus fish can be sensitive and demanding but it is definitely worth it to keep them. They are one of the most beautiful species that people love to keep at home. If you can get used to their needs and provide everything they need, you are going to have a great time taking care of them.

More often than not, there are some serious mistakes that lead to a Discus fish dying. Ensuring ideal water parameters, clean water, proper filtration and a balanced diet can be challenging at the beginning. Once you get used to it, however, keeping them in good health is going to be a breeze.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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