Discus Fish 102 – Discus Common Questions


We will talk about the behavior of your discus in this article. I will enlighten you about the basic behavioral issues that you may face keeping discus. Otherwise, I intend to answer your questions in an easy way.

Table of Contents

What Is The Minimum Tank Size For Discus Fish?

A 50 US gallons tank is the smallest tank Discus fish will thrive in since Discus fish need to be kept in a group of at least 5, 1 Discus fish should have 10 gallons of water space in a tank, Discus prefer larger tanks so the tank of 100 gallons means there will be less drastic changes in water conditions and they will have the space to wander around as they desire.

You may check my other article on how to build or set up your Discus tank aquarium tank in detail within 17 step by step guide points with my recommendations.

NOTE: If the tank is smaller than the Discus requires, e.i., putting 10 Discus into a 40 Gallons tank, then toxic ammonia will raise and Discus will die eventually. You will see signs of stress in all your Discus.

How Big Is A 10000 Gallon Fish Tank?

It is quite a big tank and by book, you can keep 1,000 Discus fish in 10,000 gallons fish tank. People usually use this size for bigger fish such as sharks. However, if you are willing to invest a lot more, then a 10,000-gallon tank can be a good investment.

Do Discus Fish Fight Each Other?

Discus fish do fight each other sometimes and might become aggressive and highly competitive for 3 reasons:

  1. Dominating the tank.
  2. Breeding time.
  3. Malnutrition.

However, Discus are actually very calm and peaceful. they do need a group of familiar Discus fish around them to feel safe since they are very sensitive and shy. If they don’t bond with their tank mates, Discus fish could possibly die eventually.

Will Discus Kill Each Other?

As a long term result of the fighting, yes, Discus fish might eventually lead another Discus to death due to continuous aggressive fight because of the exchange of the bites. You should avoid such a condition as this may result in the sickness of your Discus which takes your Discus life in danger zone.

As I stated above Discus might fight each other for three reasons, to dominate the tank, on breeding time, and as a result of malnutrition.

Why Does My Discus Keep Fighting?

Improper diet, tank, and the mates may lead to the fight between Discus fish. As a Discus fish grows, the visible signs of aggression get reduced. another reason is putting together two fish of the same gender in a breeding box could also lead to such behavior.

On the other hand, Aged Discus will peck one another, show bold colors, or develop a jaw lock. This happens in pairs when one fish is less mature than the other. It is also possible if the couple doesn’t consider one another fit for breeding so as a result, they might keep fighting.

Why Do My Discus Chasing Each Other?

An Aggressive and stressed Discus tend to chase other fish, as well as a healthier Discus fish may chase the sick one. They will body-slap or pick on Discus tank mates.

NOTE: You can take your Discus aggression into your consideration.

Can Stunted Discus Grow? Why Is My Discus Not Growing?

Yes, a stunted Discus may grow as you wish if put in a proper well-maintained tank size with other Discus of similar size of at least 5 others, however, if your Discus is not growing, then you might want to take a look at the symptoms of stunted Discus:

  1. Its shape resembles a football or a bullet.
  2. The Discus eyes are very large compared to the Discus body size.
  3. The eyes of the fish are of different sizes.
  4. The Discus eyes are not aligned, one showing higher than the other.
  5. The Discus remains the same size in the tank while other Discus fish are growing.

How Big A Stunted Discus Grow?

How big a stunted Discus can grow depends on how long and how badly the environment it was living in was, a stunted Discus cannot grow to the fullest potential if put in a bad environment; however, some stunted Discus can still grow to an average shape and size.

How Can You Tell How Old A Discus Is?

You can use this table to estimate the age of your Discus. For accurate results, you need to ensure that your Discus is healthy.

Age and Size Specifications of your Discus Fish:

[table id=27 /]

How Old Is A 2 Inch Discus?

A Discus fish of 2 inches in size has an age of 2 months.

Is Salt Good For Discus Fish?

Yes, salt is good for Discus when it is ill, aquarium salt can be used as a symptom reliever for stress when dealing with a sick Discus or when acclimating a Discus to a new home.

To be on the safe side you can use a ratio of 1 tablespoon per 10 gallons of water. It does introduce minerals that increase water hardness whereas Discus prefers softer water in general.

How Do I Know If My Discus Is Healthy?

A healthy Discus should not have symptoms of Cloudy or Dark Eyes, Clamped Fins, Dark Bodies, Wedged Shaped Discus, Discus is not eating, are the signs of unhealthy Discus. If you see also your Discus is hiding or showing white poop then these are other signs of unhealthy Discus.

To ensure you have a healthy Discus in your aquarium, you can read my other article 5 Main Tips On How To Keep Healthy Discus – Practical Guide.

How Do You Know If Discus Is Stressed?

You will know if you Discus is stressed if you find the below or some of the below symptoms:

  • Discus color becomes darker.
  • Discus is showing black bars on her body.
  • Discus is swimming erratically.
  • Discus is hiding in the dark corner of the tank.
NOTE: You can learn more about what are the 13 causes that might cause your Discus to become stress and how to treat your Discus stress.

Any change in the appearance or behavior of a fish can be a sign of stress.

As a note you can memorize these key points:

  1. Puffing at the Surface: If a fish is gasping his mouth at the surface, this is a sign of stress brought on by poor water conditions, usually a lack of oxygen.
  2. Hunger: If a Discus fish is stressed, oftentimes Discus will not eat.
  3. Sickness: Ich, characterized by white spots on the body of a Discus fish, and other diseases can appear as a result of your stress. If you observe this or any other visible ailments or sores on your fish, better to search for your symptoms on DiscusRescue.com.
  4. Awkward Swimming: When Discus are stressed, they often develop odd swimming patterns. If your Discus is swimming frantically without going anywhere, crashing at the bottom of his tank, rubbing himself on gravel or rocks, or locking his fins at his side, he may be experiencing significant stress.

Can Discus Live 7.5 pH And 8.0 pH?

Yes, Discus can be kept at 7.5-8.0 pH level but the only thing that you need to keep in mind is that the water parameter (including ph levels) consistency is more important than choosing 7.5-8.0 pH as your ideal pH level. However, an ideal water ph level for Discus is between 6.0 and 7.0. however.

NOTE: When it comes to maintaining water quality in your freshwater aquarium, pH is a significant factor. Discus prefers warm, soft, and acidic water. 

Can Discus Live In Hard Water?

Yes, Discus can live in hard water if they bred in hard water, you need to ensure from the dealer about the water quality at which Discus was kept previously and proceed according to his/her advice. Ideally, Discus prefer to soft water with the hardness level ranging from 1-4 KH.

However, Discus can also adapt to hard water but it may have risks and also requires time in order to adapt to it. so better to know your Discus breeding source like for instance, Discus from Germany breeders adapt to hard water.

NOTE: You may want to check Discus fish types to identify their differences in all terms.

Do Discus Fins Grow Back?

Yes, surely Discus fins will grow back if they were damaged by fighting, drastic change of pH (acid burn), and mistreatment by the owner. Otherwise, if fins got ragged or saw tooth damaged because of malnutrition then it will not grow. Very often, the damage portion has to be cut out to stimulate re-growth.

Why Are My Discus Fish Dying?

You Discus fish might die if you keep her in poor water quality and maintenance, you should know that this species that is known as the king of the aquarium needs a lot of hard work. You have to maintain the temperature, hardness, and pH of water for a stress-free, healthy, and growing Discus fish.

NOTE: Changing in the above parameters can prove to be the initial cause for your Discus death.

Diet and other mates also impact the nourishment of your discus. You need to review all of these in order to get fruitful results.

What Is Beefheart?

Beef heart is basically the heart of the cow where fats are removed from the heart and only heart ligaments are used as beef hearts to feed Discus. It is full of proteins and has a negligible amount of fats.

Branded Beef heart has protein and nutritional value which promotes Discus growth, whilst remaining low in fat, it is also low in sodium and high in iron and vitamin B.

NOTE: Beefheart is one of the best foods in terms of nutrients that you can feed your Discus. This can be feed to the Discus with the age of more than 3 weeks (size 1 cm).

However, this needs to be used with caution as it is not a normal part of the Discus diet in the wild.

NOTE: Excessive use of beef heart can lead to digestive issues and other related illnesses.

You can check my other article (11 Best Food For Discus – What Is The Best Food For Discus?) on how to prepare the best Discus food using Beefheart and other ingredients.

beef heart recipe and stepsHow To Make
The Best
Beef Heart
At Home?

Does Peppering On Discus Go Away?

Discus peppering

Peppering never goes away however, it can be made less noticeable by using a lighter background, peppering normally common with pigeon blood Discus.

In order to reduce the amount of black peppering on Discus fish, you need to change the colors inside your aquarium, for Discus, the best color of the gravel should be white, refrain from dark gravel and dark backgrounds, normally white gravel is the best color to make your fish look really bright and reduces the black peppering.

NOTE: Learn more about Discus peppering from my other article Why Do My Discus Have Black Spots? – Black Peppering Spots Cure.

The environment in which Discus fish were raised to determine if the black peppering on Discus fish will eventually fade away or not.

How Do You Keep Discus From Peppering?

To keep your Discus from peppering you must avoid dark colors in the aquarium, it all depends on the colors of your aquarium, if you have dark colors in the aquarium then peppering will increase with time otherwise with bright colors eventually the peppering will fade away.

NOTE: Learn more about how to treat Discus peppering from my other article Why Do My Discus Have Black Spots? – Black Peppering Spots Cure.

Why Does My Discus Shake?

Usually, Discus swimming next to another Discus and shaking their fins shows that they are asking the other fish to breed. However, this can happen if your fish had a bit of itch disease.

Discus Fish 101 Guide For Beginners

Check the version 1 of this article for step 1 beginners questions:


This is me Firas Sameer, the founder of DiscusRescue.com, I am an aquarist guy with a passion and love for Discus fishes, I am learning every day with my hobby at home and sharing the things I am learning from my experience with you.

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