Why Do Discus Lay, Swim On Its Side? – Discus Leaning Cure

Why Do Discus Lay or Swim On Its Side? complete cure

A Discus fish leaning to one side or Discus laying on the bottom of the tank is not always a symptom of a disease. It could be as a result of stress, high ammonia levels in your aquarium, among other causes. Your Discus may display this attitude at the dark corners of the aquarium.

Table of Contents

Why Does My Fish Keep Laying on Its Side?

A discus may lay or swim on its side due for different reasons which are:

  1. Normal Reaction.
  2. Symptoms of a non-disease issue.
  3. Symptoms of an infection or disease.

Discus Laying On Its Side – Normal Reaction

This could happen naturally due to two different reasons:

  1. After an extended shipmentA Discus is stressed when she has just arrived from an extended shipment, especially young discus fishes, as a result of this, she most likely will lay on her side for some while when released in a tank.
  2. Being introduced into a new tank – Discus laying on the bottom tank or float at the top of the tank is as a result of this stress, she may also behave this way because she is new in the environment and will start swimming well again from 2-5 days.

Discus Laying On Its Side – Symptoms Of A Non-Disease Issue

Symptoms Of A Non-Disease Issue

  • Swimming frantically without going anywhere – Discus can behave in this manner due to stress.
  • Discus grasping at the surface of the tank normally a result of poor water conditions.
  • Discus laying on its side due to extreme weakness in your Discus.

Prevention Tips

To prevent your Discus from laying or swimming on its side as a result of the above causes, you have to follow these instructions below:

  • Always be cautious of the levels of ammonia in your water tank, consider getting a testing kit for ammonia so that you will be able to detect it.
  • It is very vital to maintain a standard pH level for your discus, the standard pH for discus fish is (~6.5 and Hardness 4.0), hence anything above 7 or below 6 the discus will start showing stress reactions.
  • A very high temperature or low temperature in the aquarium can cause a tremendous amount of stress for your discus, which will cause it to swim or lay on its side. The temperature of the aquarium should be maintained between 80º – 86º Fahrenheit (around 29º – 34ºc).
  • Avoid high salinity in your aquarium.
  • Always use dechlorinated water, because most municipals add chlorine to their water to make it clean, you must always test the water before pouring into your aquarium, a solution like Seachem prime can do the work.
  • Feed your discus well, not to overfeed her because that might cause her to bloat, but the content of her meal should be rich so that she’s not malnourished.

Discus Laying On Its Side – Symptoms Of Infection or Disease

A discus fish can lean or swim on its side because of underlying infection or diseases such as:

  1. Discus Plague.
  2. Swim Bladder Disorder.

Discus Plague


Discus Plague Symptoms

  • Rapid and heavy breathing up to 3 breaths per second, in the early stages of this disease.
  • Swiming up and down randomly in the aquarium occurs in the early stage of this disease, mostly in young fishes.
  • Discus staying in the dark corners near the top or bottom of the tank.
  • Leaning to one side at the top or bottom of the tank.
  • Increasing black spots on the discus’ skin.
  • Loss of appetite or hiding behind aquarium decorations and filters with clamped fins.
  • Turning black in color, especially in the blue and brown strains.
  • Producing excessive mucus and slime coat.
  • Scratching and rubbing against aquarium objects; they may also start darting and twitching.
  • Severe fin rot and columnaris.
  • White patches and on fish’s skin; these white spots usually are caused by secondary infections such as external parasites, bacteria, and fungi.
  • Cloudy and smelly water due to a large amount of slime coat and protein.

Discus Plague Disease Details and Cause

Discus Plague, also known as discus black disease, is a hazardous viral disease that is highly contagious, which can result in discus sitting on the bottom of the tank or Discus laying on side at the bottom of the tank. It is like an airborne disease that works in water.

Because of this airborne virus, all the aquariums and fishes in the same building can be exposed to this discus plague without having to share equipment.

NOTE: If you quarantine an infected Discus in a separate tank of the same building, the plague virus can go airborne and spread to all other tanks of healthy fishes.

Any little contact with equipment or even driftwood that is infected can infect your tank with Discus plague.

Discus Plague Treatment Steps

IMPORTANT: To cure your discus having the plague disease, better to follow the 15 steps guide on how to treat it in deeply detailed step by step from my other article 15 Steps To Cure Discus Plague aka Black Death Disease.
  • Increase the temperature of the aquarium to about 86º Fahrenheit. This will increase the immunity of the discus fishes and prevent the discus plague from killing them.
  • To control secondary infections in discus fishes, a general treatment of external parasites and fungal infections can be effective. Medications Like API General Cure™ Powder and Seachem Paraguard are some of the best examples.
Seachem Paraguard
Api general cure powder
  • Other causes of death in a plague-infected Discus is a bacterial infection. Broad-spectrum antibiotics like ciprofloxacin can help to prevent, control, or treat many types of bacterial infections.
  • Heavy water change is the key, you have to do at least one 100% water change every 24 hours and before you administer the new dosage of medicine.

Future Prevention Tips

  • Isolate new fishes in a separate building and tank and observe before taking them to the main aquarium.
  • Don’t introduce a new discus to an aquarium that had the plague before 6 months.
  • Build the immunity of your discus by providing them a perfect environment.

Swim Bladder Disorder


Disease Details and Causes

Swim bladder disease or disorder is one of the common causes of loss of balance in discus and Discus Leaning on its side. When this is observed, instant medical attention should be given to the discus fish.

Swim bladder disorder can happen as a result of a collection of issues upsetting the bladder. In swimming, Discus leaning on its side, and discus sitting at the bottom tank.

NOTE: If you find your fish tipping on the side it shows that the fish is no longer in control of the air that goes in and out of its swim bladder as a result of this disorder.

Treatment Steps

IMPORTANT: For a complete discus swim bladder disorder cure steps, you need to visit my other deep detailed treatment step by step at How Do You Treat Discus Swim Bladder Disorder? – Swim Bladder Cure.
  • Allow your fish fast for at least 3 days since bloating is the major cause of this disease.
  • Avoid feeding fishes that have this disorder as much as you used to.
  • Increase the temperature of water in the tank, because the low temperature can cause indigestion.
  • You are free to feed your fish after the third day, but not with dry food. You can go to skinned peas or cooked soft food.
  • Keep the volume of the water low; it will help the fish conserve energy while trying to swim their way up and down in the water.
  • Add a little amount of aquarium salt.
  • Hand-feeding your fish will help if your fish can’t move to eat well.

Future Prevention Tips

  • Keep the tank clean and perform regular water changes because poor water conditions cause fish to be more susceptible to infections.
  • Keep the water temperature a bit higher, this will help in digestion, and possibly avoid constipation, which is another potential cause of swim bladder problems.
  • Feed only high-quality foods and avoid feeding them dry foods.
  • Always thaw frozen foods thoroughly before placing them in the tank. For fish that gulp air when feeding at the surface, try switching to sinking foods.
  • Feed smaller portions, do not overfeed at all, so fish will not overeat and watch the total amount you feed throughout the week.


As an aquarist, you must be able to discover why your discus fish is tilting or laying flat on its side at the bottom tank. It is very important to continually check your aquarium water and fishes knowing that any change in the behavior of a fish can be a sign of disease or stress in the tank. Early treatment is always more effective.


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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