Discus Fish Disease

Are you having trouble with your discus fish? Do they seem to be getting sick frequently, and no matter what you do, you can’t seem to get them healthy again? If so, then you may be dealing with a disease.

Despite the fact that Discus fish are one of the most beautiful aquarium fish around, they can also be susceptible to a variety of diseases.

And in order to keep your discus healthy and happy, it is important to be familiar with the most common discus fish diseases, how to treat them, and how to prevent them from occurring in the first place.

This article will provide you with all of the information you need and more!

So keep reading for everything you need to know about Discus Fish Disease.

Common Discu Fish Diseases

Before we jump into the disease, first we need to know that there are two types of discus fish disease; external and internal.

External discus fish disease, as you might imagine, affects the outside of your pet discus fish’s body.

These diseases are typically caused by parasites or injuries that the discus fish has sustained.

Also, they are rather easy to recognize if you pay attention to your fish on a regular basis, as they make readily apparent signals on the outside.

If your fish’s behavior, coat color, or texture suddenly changes, that means you need to treat it as fast as you can.

Internal discus fish disease, on the other hand, affects your pet on the inside.

These diseases are usually harder to identify on your own, as they can be caused by a number of different things.

In this section, we will discus the most common disease whether it was external or internal.

So, lets go to the first disease.

a. External Diseases

1. Toxic Aluminum

The pH balance in your aquarium water must be closely monitored for discus fish.

Any pH values greater than or less than 8 and 5, respectively, can be fatal to your beloved fish.

If your pH falls into either of these two ranges, this deadly disease will take a place and cause serious difficulties in the functioning of your fish’s gills.

  • Low or high pH levels
  • Using aluminum products in the aquarium water
  • A sudden change in the behavior of your fish
  • Floating at the top of the aquarium, dazed and confused
  • Change the aquarium water
  • Adjust the pH level between 5.5 and 8
  • Quarantine the infected fish and treat it with antibiotics
  • Check the pH level regularly and make sure all water is in the pH range between 5.5 and 8.0
  • Make certain that no aluminum products are used in the aquarium water (unless they have been created specifically for aquarium use and the finish has not been damaged).

2. Fungal Infections

Fungal infection is a common problem among Discus fish, and it most frequently affects the fish’s external tissues.

Your discus fish may easily fall prey to fungal illnesses at specific locations on their bodies because fungus spores can readily be found in water and attach to the bodies of your fish, especially if they have wounds.

Fungal infections are generally unavoidable as they occur secondary to an injury or a parasitic invasion of the fish’s skin, and the worst part is that this illness may kill your fish.

  • Spores of existing fungus were discovered in the aquarium
  • Wounds or fractures on the fish’s skin
  • Poor water quality
  • Other fish with recurring fungal infections
  • A cottony or feathery attachment surrounds the break/wound on the fish’s body.
  • Antibiotics such as Triple Sulpha and Tetracycline are frequently used.
  • Wounds and fractures on the skin should be treated as soon as possible
  • Maintain your water quality
  • Remove any dead fish as soon as possible
  • Use antifungals
  • Add some salt to your aquarium

3. Parasitic Anchor Worms

The Anchor Worm is a type of parasitic crustacean (a species of the Lernea genus) that buries its head deep into the fish’s muscle tissue.

  • Poor water quality
  • The addition of a new fish in the tank that already has the worm
  • Skipping appropriate quarantine
  • Aquatic plants in the tank
  • Skin irritation
  • The parasite’s whitish-green threadlike body can be seen protruding from the fish’s skin
  • Apply potassium permanganate dips or salt dips.
  • Use antiparasitic.
  • Applying topical antibiotic ointment to the infected area
  • Use organophosphates or diflubenzuron with the veterinarian’s consent.
  • Any additional product in the tank must be properly quarantined.
  • The cleanliness of the water must be maintained.

4. White Spot Infections

The white spot, or “Ich,” is a severe tropical fish disease that discus fish breeders dread.

This infection is not only highly transmissible, but it also has an excellent mortality rate when left untreated in your aquarium.

  • It’s caused by a microscopic parasite called Ichthyophthirius multifiliis, which causes white spot disease in fresh water fish (also known as ick or white spot disease).
  • Swimming around erratically
  • Lethargy and emaciation
  • Tiny white spots & patches appear on the gills and remainder of the body.
  • Fish lose appetite.
  • Perform a partial water change every few days, and keep the aquarium lights off for as much of the day as feasible (this will aid in the prevention of outbreaks if you don’t have medication available).
  • Use Ich medication such as Acriflavine (available under a variety of brand names).
  • Water changes should be performed on a weekly basis.
  • Maintain excellent water quality.
  • Don’t overcrowd the tank.

5. Cloudy Eye Infection

Cloudy eye infection is a typical eye fungus illness, and it’s a result of environmental issues.

This sickness can blind the fish by damaging its pupil and also it might be mistaken for a sign of other uncommon illnesses.

  • Bacterial infection.
  • Parasitic infection.
  • Poor water quality
  • Eye injury
  • Physical stress that is caused by illness and fish transport.
  • Cloudy or opaque eyes.
  • loss of hues in the fins and/or skin. 
  • Fish may rub against objects
  • Fish become lethargic
  • Apply a topical antifungal medication like API Fungus Cure to your feet.
  • Quarantine the infected fish.
  • Frequent water testing
  • Regular water changes
  • Maintaining the water temperature
  • Maintaining water quality and its pH level
  • Replacing the carbon filter on a regular basis

6. Columnaris Disease

Mouth and fin rot (also known as Columnaris) is a bacterial illness that can be deadly to aquarium fish.

Althoughregularly it has been around since the 1940s when antibiotics were not readily available to hobbyists, it continues to wreak havoc in our community today.

It can also spread to other fish in the same tank very quickly, especially if they are housed together.

  • Poor water quality
  • The aquarium needs more aeration
  • Sudden changes in temperature or pH
  •  Overcrowding
  • Adding new fish that are infected with the disease
  • It can occur as a secondary infection from other diseases, such as fin rot and Velvet (gold dust disease), or due to aggressive behaviors.
  • Small white dots may be seen on the fins, these spots will grow in size then they will vanish in the fish body.
  • The body may also manifest symptoms such as redness and inflammation.
  • Remove the infected fish to a separate aquarium so that it does not spread the infection to other fish.
  • Using an antibiotic solution to treat the tank will allow you to eliminate the bacteria that are causing the sickness. There are several antibiotics that can be used to cure it, such as Furan-2 and Furan-3.
  • Make regular water changes
  • Vacuuming the gravel is a must, as it can get clogged with detritus and algae.
  • Replace 20-30% of your filter media every week or two (or more if necessary)
  • Don’t allow your fish to go hungry by providing them with plenty of food.
  • Remove any dead or dying plants from the surrounding area because these would also cause difficulties for them.

7. Discus Plague

The discus plague, also known as Black Disease, is a viral illness that causes fish to have black spots on their bodies.

It’s a contagious illness that affects only discus and can spread from one tank to the next or from one fish to the next.

  • Airborne virus
  • Previously infected discus fish were added to the aquarium.
  • Aquarium plant or equipment that is contaminated with the virus
  • Rubbing against objects.
  • Rapid and heavy breathing
  • Clamping of fins
  • Black spots on the skin
  • Fish trying to hide in the dark areas
  • Loss of appetite in the fish
  • Cloudy and/or smelly water
  • Swimming motions that are jerky.

There is no known cure for Discus Plage sickness at this time, but there are a few broad treatment procedures that may be employed.

  • 30%-50% water changes every week
  • Increase the water’s temperature to 33.33°C for better metabolic function and stronger immunity in fish.
  • Control secondary infections
  • Use of broad-spectrum antibiotics such as ciprofloxacin
  • Use air stones in the tank to help the afflicted fish breathe more easily.
  • Water quality must be maintained.
  • Do not add any Discus previously diagnosed with the discus plague, since they may serve as a vehicle for the disease’s transmission.
  • Treat the skin injuries and wounds right away.
  • Quarantine the infected fish.

8. Fin and Tail Rot

Fin and tail rot is a kind of fish disease that can occur to any fish not only Discus fish.

These infections are caused by a group of bacteria known as Aeromonas.

These bacteria enter discus body through wounds particularly after being attacked by another fish.

  • Poor water quality
  • Sudden temperature changes
  • Holes in the fins or discoloration of them. 
  • Dark spots appear on the body of the fish
  • Use antibiotics if the infection is relatively mild.
  • If the condition is more severe, it will necessitate more intensive treatments that are given through intramuscular injections or intravenously.
  • Regularly check the water quality in the tank.
  • Keep the pet away from toxic chemicals (such as formalin).

b. Internal Diseases

1. Loss of Balance or Headstanding

  • Poor water quality
  • Digestive system blockages
  • Swimbladder trouble
  • Blood flagellates
  • Weird flip-flop antics in the tank
  • Check all the parameters mentioned above.
  • Treat the infected fish by adding salt and antibiotics to the aquaruim.
  • Chnage your aquarium water
  • Always check your water parameters
  • Do regular water changes

2. Fish Tuberculosis

Fish tuberculosis is a secondary disease that is caused by the tuberculosis mycobacteria that is found in the aquarium gravel, food remnants, and other debris.

Note: The treatment of this fish sickness should be done with care since the bacteria may easily infect humans via open wounds and cuts.

  • Poor living conditions
  • Overcrowding
  • Infected fish
  • Tuberculosis are bloating
  • Emaciation
  • Jerky movements
  • Skin sores.
  • Popeye, loss of appetite, and odd spinal curvatures are some other symptoms you might notice.
  • Vitamin B-6 and Kanamycin Combination
  • Quarantining the infected fish
  • Remove all the inhabitant from the tank, and clean all the decorations and accessories.
  • Avoid overcrowding the tank
  • Avoid introducing sick fishes into the tank
  • Make regular water changes

3. Dropsy and Popeye

Dropsy, and popeye are common internal discus fish problems. It occurs as a result of fluid retention behind the eye or along the spine, causing the eyes to protrude.

  • Bacterial infections
  • Physical damage to the fish’s eyes. 
  • Poor nutrition
  • The eye of a fish may become bloated and protrude from the head
  • It can frequently get worse until the eye is completely out of its socket.
  • If one eye goes blind, the other one will compensate for the damaged one until it too becomes affected by popeye.
  • To prevent the spread of infection, move them to a separate tank and treat them with Kanamycin sulfate or Nitrofurazone according to a prescription.
  • If your fish do not respond to Kanamycin sulfate or Nitrofurazone, a bacterial infection may occur; therefore, if no results are produced after using a treatment with Kanamycin sulfate or Nitrofurazone, add 1 tbsp of aquarium salt for each 5 gallons.
  • Once your fish have been treated, carefully move them back into the main tank and monitor for any signs of popeye relapse.
  • Repeat therapy and use 1 tablespoon of aquarium salt per 5 gallons if popeye reappears.
  • Provide your discus with the water parameters they deserve
  • Use a filter for biological filtration, such as an under gravel filter or sponge filter. This allows you to remove ammonia before it can harm your fish by causing Pop Eye disease or other illnesses by using a Biological Filter.
  • Feed your fish a high-quality food
  • Change about 20% of the water in the aquarium every week and vacuum the gravel with a siphon or gravel vacuum to keep it clean and free of decaying plant material.
  • Any dead animals or decomposing plant material in the tank must be removed immediately.

4. Hexamitiasis

This internal protozoan infection is not only a disease that affects your fish, but it is also thought to be contagious.

  • Overcrowding
  • Poor water conditions
  • Nutritional deficiencies
  • Stressful situations like bullying by other fish
  • Whitish feces with slimy textures
  • Unusual fish behavior like swimming backward and hiding in the back,
  • Emaciation, and loss of appetite
  • Lethargy, listlessness, and dimness of skin and eyes are all symptoms of the illness that appear in later stages.
  • Isolate the infected fish
  • Use antibiotics such as Metronidazole
  • Make 50% water changes every day
  • Raise water temperature to 33.33°C and 37.78°
  • Always check your water parameters
  • Regular change of aquarium water
  • Avoid overcrowding
  • Quarantine the new fish before producing it to your aquarium

5. Tapeworms

Infections with tapeworms are also frequent in discus fish and can be lethal if not treated promptly.

Tapeworms are enormous worms that weaken fish by leaving holes in their bodies.

They do not kill the fish directly, but the wounds they leave behind make them vulnerable to parasite assaults.

  • Poor water quality
  • Poor diet
  • The introduction of a new sick fish to the tank
  • Sleepiness and lethargy.
  • Problems with the digestive system in older fish.
  • Bodyweight loss.
  • Quarantine the infected fish
  • Use antibiotics such as Praziquantel
  • Keep the tank clean and sanitary.
  • Regular change of aquarium water.
  • Test the new fish for the disease.

6. Head and Lateral Line Erosion (HLLE)

Hole-in-the-head (HITH) is a common name for this disease, which is classified as chronic and nonfatal.

It may be extremely challenging, even though it is not immediately fatal.

This illness can make your fish anorexic and increase their risk of contracting secondary bacterial and parasitic diseases.

  • Poor water quality
  • Poor diet
  • Activated Carbon
  • Skin de-pigmentation (loss of color)
  • Small craters (holes) form near the head and a lateral line on the body of the fish.
Treatment & Prevention
  • Feed your fish a varied diet that includes seaweed and Selcon’s vitamin supplement to promote healthy growth.
  • Keep your water parameters within a healthy and safe range.
  • Use high-quality carbon and reduce flow rates to avoid generating abrasive particles into the water supply.


How Can I Prevent My Discus Fish From Getting Sick?

One of the best ways you can prevent your discus fish from getting sick is to maintain a clean tank.

This does not only mean regular water changes, but it also means having a clean filter and regularly cleaned gravel as well as plants and decor in the tank.

You should do daily observations on your fish for any abnormal behavior or appearance.   

Also, you should keep an eye on their feces to make sure they are not discolored or if there is blood in it.

Additionally, exercise caution when introducing new fish into the tank and quarantine them before adding them in.

Finally, make sure not to overcrowd your tank and make sure that all of your fish are about the same size.

If you follow these five tips, you can avoid most illnesses in discus fish and maintain a healthy and happy community of fish!

How Do I Know If My Discus Fish Is Sick?

If your discus fish has contracted an illness, there are several signs you should be looking for.

The first is  frequent  loss of appetite.

If your fish stops eating for a period of more than two days, it is probably sick and should be watched carefully.

Next, you should look out for loss of coloration or pigmentation, black feces or spots on the body or fins.

Finally, watch the fish for abnormal behavior like hiding in dark places, acting abnormally towards other fish, or darting back and forth.

All of these are symptoms that your discus is sick and you need to deal with it ASAP.

Why Is My Discus Fish Getting Sick?

There are many reasons why your discus might contract an illness.

One of the most common reasons is poor water quality, so make sure to keep your tank clean and free of ammonia buildup.

Another common reason is a new fish has been introduced to the tank or an existing one has been removed.

This can interfere with the natural bacteria in the tank, which causes an imbalance that leads to illness.

Make sure not to overfeed your discus as well, as this can lead to the water becoming discolored, which can also harm your fish.

Finally, poor diet can weaken your fish’s immune system and make them more vulnerable to illness.

Why Is My New Discus Fish Sick?

One of the most common reasons a new discus fish will come down with an illness is because it was introduced to the tank too early.

You should avoid putting new fish in your tank until the ammonia and nitrites fall to zero.

This can take anywhere from 3-6 weeks depending on the size of the tank and whether or not there are other, existing fish in the tank.

Why Is My Old Discus Fish Getting Sick?

The reason an old discus fish becomes sick is because their immune system has weakened over time.

As a result, it will become more susceptible to illnesses and infections.

In this case, it may be best to take the fish out of the tank and treat it separately with a hospital tank (which is basically an empty 10 gallon tank with a filter and heater).

Only keep the fish in here for about one week, as this will be enough time to treat any infections.

After this, put the fish back into the tank slowly over a period of about three weeks so that it can get used to the water again.

How Can I Prevent a Disease From Spreading?

One of the most effective ways to prevent a disease from spreading is to do regular tank maintenance.

This means cleaning out the gravel, changing out the filter cartridge, and doing a large water change.

Also, be sure to keep your tank free of any unnecessary clutter as this can create a hiding spot for potential disease vectors.

Finally, keep a close eye on your fish and quarantine new ones before adding them to the tank.

Last Words

There are several diseases that discus fish can get, but don’t worry: you’ll always have discus fish medications on hand.

Many popular drugs and treatments are available on the market, as well as other fish supplies.

However, you can prevent a lot of illnesses by maintaining your aquarium water clean, feeding your fish fresh food, and prodding them with the right water conditions.

We hope you have enjoyed this article as much as we did.

If you still have any questions, please share them with us in the comment section below.