Are Discus Fish Aggressive?

Are Discus Fish Aggressive?

Discus fish are cute buddies that can make a great addition to your home aquarium. But are discus fish little buddies aggressive?

Generally speaking, discus fish are not an aggressive species. In fact, they are relatively peaceful fish that get along well with other fish.

However, there are always exceptions to the rule. Just like with any other fish, there are some things that can drive them to aggression.

In this article, I will share every possible reason that can make your discus fish aggression and what you can do to minimize the risk of aggression in them.

Are Discus Fish Territorial?

Discus fish are not a territorial species. However, they do like their space and prefer to have some room to move around in their discus tank.

If you keep them in a cramped up space, then it is likely that they will become aggressive towards each other as they will be constantly bumping into each other.

Also, when you keep more than one male discus fish in a discus tank, then they might start fighting over dominant fish leading to some serious aggression issues.

Overall, as long as you give them what they need in terms of space, food, and water quality, you will see them getting together just like a little family and minding their own business most of the time!

Is Female Discus Aggressive?

Female discus fish are very peaceful in comparison to male discus. However, when defending their eggs, they can become quite aggressive and can even attack their mate or other tank mates.

So, if you see your little girl getting a little too feisty, then it is probably because she is protecting her eggs. Once their babies emerge, they will go back to being their usual selves.

Also, females may establish a hierarchy to mark their territory, but their fights are less violent than those of males. Consequently, the chances that they might hurt each other are quite low.

Moreover, if the male discus fish are constantly bothering them for mating purposes, female discus fish can become aggressive. Thus, you should have a higher ratio of females to males (3:1) so that the females can have some peace.

Why Are My Discus Fish Getting Aggressive?

They Are Establishing Pecking Order

Discus fish are social creatures and love to be in a group. When you first introduce them to the tank, they will start establishing their pecking order.

This process can take some time and during this period, you could see some aggression as they try to figure out who is the boss. However, once they establish their hierarchy, things will start to settle down.

Improper Aquarium Conditions

When your discus feel they are living in an unsafe or unsuitable environment, they can try to escape by jumping out of the tank which can be fatal for them.

Some of the common aquarium conditions that can lead to aggression in discus are:

  • Unhealthy water conditions: When the water contains much ammonia or nitrites, it can trigger aggression in your fish as they try to escape the toxic environment if they can’t escape it will be a sick discus fish
  • Inconsistent water temperature: They are tropical fish and prefer a constant water temperature between 82-86 degrees Fahrenheit. Any drastic changes in the water temperature can lead to aggression as they try to cope with the change
  • Not enough hiding spots: Discus fish are timid creatures and need a lot of hiding spots in their tank so that they can feel safe. If they don’t have enough places to hide, they will feel lost and confused
  • Too much light: These cuties are sensitive to light and need a dimly lit tank so that they can feel comfortable. Thus, when they are constantly exposed to bright light, their mental health can suffer making them very aggressive


When you are hungry, you tend to get cranky, right? Well, the same goes for discus fish.

If they are not getting enough food or the right type of food, they can become aggressive as their hunger builds up.

Also, this can lead to low energy levels and a weakened immune system, making them more susceptible to bullies from other fish. As a result, you might see them getting into more fights.

Breeding Season

During the breeding season, the male discus fish can be quite aggressive as they try to mate with the female discus.

In an attempt to attract the female, this little guy will start to display some very aggressive behaviors such as chasing after her, nipping at her fins, and even trying to bite her.

While this might look alarming, it is actually quite normal behavior and you don’t need to worry too much about it.

Once they lay their eggs, this aggression will be focused on the eggs and their fry (baby fish). Your new mummy will be very protective of her fry and might even start attacking you if she feels that you are a threat to them.

Moreover, when there are more males than females in the tank, the males can start fighting with each other for the attention of the female.


Discus territory can be the most significant source of aggression in these fish. When there are too many fish in the tank, they will start to feel cramped and their stress levels will go up.

As a result, you might see them nipping at each other’s fins or tails as they try to establish their own space. In extreme cases, they might even start biting each other which can lead to fatal injuries.

Different Discus Sizes

Due to their hierarchical nature, you will often see aggression from the larger discus fish towards the smaller ones.

The bigger ones will usually dominate the tank and chase the smaller discus around or even bite them. This can be extremely stressful for the little ones and might even lead to extreme anxiety or depression.

How to Stop Discus Fish from Getting Aggressive?

Spread Food All Around The Tank

One of the simplest ways to reduce aggression in your discus fish is to spread food all around the tank so that everyone can have a fair share.

This way, the bigger discus will not be able to hog all the food and the smaller ones will not have to compete with them for food. As a result, the stress levels will go down and the aggression will start to dissipate.

Establish a Planted Aquarium

Recreating a natural environment for your discus fish can do wonders for their overall well-being. To do this, you can establish a planted aquarium which will provide them with plenty of hiding spots and make them feel more comfortable.

The plants will also help to keep the water quality in check and provide them with some much-needed nutrients.

However, when choosing a plant, be sure it is non-toxic to your discus fish since their skin is extremely sensitive and permeable, and certain plants might easily harm them.

Change Your Aquarium Water Regularly

Clean water will make the tank more like their natural habitat and reduce the stress levels in your discus fish tank. As a result, they will be less likely to act out aggressively toward each other.

For this reason, you need to change your aquarium water on a regular basis (at least once a week) and vacuum the gravel to remove any build-up of waste.

To keep the water clean and free of toxins, you can also add a filtration system to your aquarium. This will help to remove any harmful bacteria or chemicals from the water and make it safer for your fish to live in.

Keep Them in Bigger Group

Since discus fish are sociable species, they do best when they live in a group. Thus, having their own kind around will make them feel more at ease and will give them the sense of belonging that they desire.

For this purpose, you should keep them in a group of at least five to six individuals. This way, they will be able to establish a hierarchy and will not have to compete with each other for food or space.

Separate the Aggressive Discus Fish

In case you do everything right but your discus fish are still acting aggressively towards each other, then the best course of action would be to separate them into different tanks.

This way, they will have their own space and will not have to compete with each other for food or territory.

If you have a very large tank, you can also try to partition it so that each fish has its own section. This will help to reduce the aggression and allow them to coexist peacefully.

Is It Possible for Discus Fish to Kill Each Other?

Discus will never kill each other due to aggression. However, if the aggression gets too out of hand, it can cause some serious injuries.

The most common injuries that occur due to aggression are ripped fins and tails. In severe cases, the fish might even bite each other which can lead to fatal wounds.

Thus, it is important to keep an eye on your discus fish and make sure that they are not causing any harm to each other. If you see any signs of aggression, be sure to take action immediately to prevent any further damage.

Last Words

Discus fish are beautiful creatures that make for a great addition to any aquarium. However, they can be quite aggressive discus at times and might even hurt each other if the aggression gets out of hand.

Thus, it is important to take some measures to reduce their aggression and keep them from harming each other. With a little bit of care and effort, you can easily keep your discus fish happy and healthy fish.

I hope this article was of help to you. If you have any further questions or concerns, please feel free to reach out to us!