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The Real Meaning For Discus Stress Bars On Your Fish!

The popularity of keeping discus in aquariums is on the rise again due to their beautiful patterns and unique colors and although a large number of beginners are adding discus to their tanks, they really are not a beginner friendly fish to keep.

This is why we have seen so many people reaching out and asking questions about noticing discus stress bars on their fish due to there being a potential problem with the fish.

Discus stress bars are commonly show as a sign of stress and anxiety in the fish but discus can also display “stress bars” for a number of other common reasons so they are not always a sign of the discus being stressed.

Other reasons that discuss will show these stress bars include the fish trying to attract a mate, trying to scare off another fish, due to illness, and in rare cases as a way to try and camouflage itself.

Unfortunately for the fish keeper, the majority of discus are only able to show one type of stress bar that they use for all occasions making it difficult to try and work out what the actual problem is with your fish.

Still, we will be going over some of the more common issues in our article below in an attempt to try and help as many of our readers as possible who are noticed stress bars showing up on their pet discus.

What Do Discus Stress Bars Look Like?

Discus stress bars are dark bars on some species of discus fish that are usually black but can also be dark brown or dark red depending on the color of the fish.

Technically, the bars are always there on the fish but the discus can flare their stress bars to make them visible in certain situations such as when the fish is stressed or anxious.

Depending on the lighting for your tank, it can sometimes look as though your discus is constantly showing its stress bars even if there is nothing wrong with the fish.

You can usually confirm if the stress bars are intentionally being shown by your discus or if it is simply due to the lighting in your tank by turning the lighting unit for your aquarium off for a minute while you check to see if the stress bars are still visible.

Although stress bars are most commonly thought of as a way for the discus to show signs of stress or being anxious, this is not the only reason that discus fish will flush their stress bars.

We have lost count of the number of people who are worrying about their discus on social media due to it showing stress bars when it is more likely that the fish is just looking for a mate but it can be difficult to work out exactly why your discus are showing its stress bars making confusion common amongst fish keepers who keep the species in their tanks.

Can All Discus Show Stress Bars?

Not all species of discus have stress bars with Pigeon Blood discus and a few other species of discus showing stress spots rather than stress bars.

These stress spots are used for the same reasons as stress bars and are usually the same color with black spots being the most common with dark brown and dark red spots being less common.

Due to the natural pattern of Pigeon Blood discus and the other species that show stress spots instead of stress bars having naturally occurring spots on them, it can be a little tricky to confirm that it is actually stress spots that you are seeing and not their natural pattern.

One trick that may be able to help you confirm the issue is to check the face of the fish as their natural spots are rarely seen in this area where as stress spots are common if shown around the face and side of the head, especially near the nose of the fish.

We have seen some people on social media report that their discus tends to lose color when stressed rather than show stress spots or stress bars.

Although this could be accurate, it is far more likely that a discus that is having its color fade is having problems with its diet or its water temperatures and fixing those issues will be enough to bring the color of your fish back without any further issue.

How Do You Know If Your Discus Is Stressed?

Due to discus stress bars being used for a number of different reasons in the fish, it is usually a good idea to look for other signs of stress in your discus in addition to stress bars.

Other common signs of stress in discus include frantically swimming for no reason, crashing into the substrate in its tank, rubbing itself against the substrate or rocks in its tanks or keeping its fins clamped for a prolonged period of time.

In some rare situations, a discus may try to hide when stressed too but a discus in hiding is not enough to confirm stress on its own as there are a number of different reasons that discus will hide.

You can also look for obvious causes of stress in the tank that may cause your discus to become stressed helping to give you an indication of the reason that your fish is showing its stress bars.

Common causes of stress in discus include but are not limited to aggression from its tank mates, over crowding in its tank, being in a tank that is too small for the fish, suffering from a parasitic infection, and poor water parameters.

Thankfully, most of these are not only easy to confirm but they are also usually easy to fix for the majority of people making it very easy for your to narrow down the potential reason that your discus stress bars are showing.

Why Does My Discus Have Black Stripes?

The most common reason that a discus will have black stripes on it is due to being stressed or anxious and the fish showing its stress bars. In rare situations, a discus may have natural black or dark color stripes on it as a part of its normal pattern.

In rare situations, a discus can have black stipes as a source of trauma to the fish, usually due to aggression from its tank mates.

If this is one of the reasons that your discus is showing black stripes then it is highly likely that the fish will also be stressed out due to aggression from its tank mates and that the fish will probably be showing stress bars too.

In most cases, if you can see black stripes on your discus then it is probably due to the fish either choosing to show its stress bars or due to the lighting in your tank making it easier to see the stress bars of your fish.

As we touched on earlier in the article, turning your aquarium lighting off for a minute to check if you can still see the stress bars on your discus is a quick and easy way to confirm this though.

What Else Can Discus Stress Bars Indicate?

Discus stress bars are not only used to show signs of stress but they are also used when looking for a mate, when trying to scare off other fish, when ill, and fighting other discus, and in rare situations as an attempt at camouflage too.

Some aquarium lighting units can also make it easier to see the stress bars on your discus too even if there is no problem with your fish so keep this in mind.

Due to the most common reason that your discus will show its stress bars for an extended period of time being problems with stress or anxiety, it only makes sense to start your investigation into the cause of the stress bars there.

We have covered the more common causes of stress in discus earlier in the article but discus really can be a hypersensitive fish and even minor things can stress them out, this is why we mentioned that discus are not beginner friendly fish back at the start of the article.

If your discus is showing its stress bars due to being ill, there will almost always be additional symptoms showing on the fish helping you narrow this down as the cause of the stress bars.

The majority of people will usually keep their discus in a discus only tank but if you are keeping discus in a community tank then the fish may be flaring its stress bars as an attempt at camouflaging to try and hide itself.


That brings our article going over discus stress bars to an end. We hope that we have been able to help you better understand why your pet discus fish may be showing its stress bars as people often instantly think that there is a problem with their fish. Although stress bars on a discus can indicate a potential problem, they can be shown for other reasons too so always try to investigate before taking any action if possible.