Platy Fish Diseases, Parasites & Remedies

Platy fish can fall victims to many ailments, some preventable, some curable, others fatal. In any event, knowing about the most common platy fish diseases, parasites and illnesses as well as their remedies can put you at an advantage in overcoming the disease.

In this article, I will talk about the diseases you’re most likely to encounter while keeping platies. Where applicable, I’ll also point out the current treatments and remedies for these diseases.

Some diseases affecting platies aren’t curable and prevention is the only way to avoid the disease. To this end, I will offer you easy-to-implement advice on how to prevent platy diseases.


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Common Platy Diseases & Treatments

Each disease has its own set of symptoms that you should know about, so you’ll know how to spot the disease and take the necessary steps to treat it.

Some symptoms may overlap, making it difficult to distinguish between diseases. Therefore, I recommend that you seek out the advice of a licensed veterinarian whenever you’re not sure which diseases do the symptoms point to.

1.  Ich Disease

A highly-contagious disease, ich or ick disease is caused by an ectoparasite, which thrives when the water quality in the aquarium is poor or when fish are exposed to extreme stress.

It can be introduced into the aquarium by other fish, plants or decorations that you place into the plat fish tank.


If your platy fish have contracted ich disease, they’ll usually display the following symptoms:

  • White, salt grain-like spots appear on the body of your platies;
  • Your platies will experience breathing difficulties;
  • You’ll notice them rubbing themselves against hard surfaces in your aquarium.

How to Treat Ich:

Ick is easy to detect and it’s a curable disease. Treatment for ick involves:

  • Gradually increasing the water temperature to 80 F (this will encourage the parasite to fall off the fish);
  • Adding Seachem Paraguard at the recommended dose or adding aquarium salt at 1 teaspoon per gallon;
  • Treat infected fish in a hospital tank but apply treatment at tank level;
  • Keep up the treatment for 4-7 days;
  • Gradually decrease temperature to normal levels;
  • Perform a 70% water change and thoroughly clean the substrate.

2.  Swim Bladder Disease

The swim bladder is an organ that affects the buoyancy of your fish. If this gas-filled organ becomes dysfunctional, your fish will have trouble swimming.

It can be caused by poor water conditions, stress, or high levels of ammonia.


  • Difficulty swimming;
  • Floating at an angle or upside down;
  • Balance issues;
  • Distended belly.

Treatment of swim bladder disease involves addressing the triggering factors – stress and water quality.

Inflammation of the swim bladder is a different disease that’s caused by a virus and unfortunately cannot be treated. Fish with this disease should be removed from the tank and disposed of.

If your fish are suffering from swim bladder inflammation, you’ll notice that your fish are swimming with their head pointed to the substrate and their bellies are enlarged.

3.  Fin & Tail Rot

Both bacteria and fungi can cause fin and tail rot disease. Because bacteria and fungi are targeted with different types of medications, it’s sometimes difficult to distinguish the cause and administer the right medication.

Poor water conditions and ammonia burns are the triggering factors of this disease.


  • In the absence of an injury if fins and tail start rotting, the cause if most likely a bacterial infection;
  • If injury (e.g. other fish injured your platies) is present and tail or fin started rotting, the cause is most likely a fungus;
  • Fins or tail looking like it has been chewed up, shredded or stuck together;
  • White milky areas on body in advanced stages.

How to Treat Fin and Tail Rot:

  • Set up a quarantine tank for diseased platy fish;
  • If the disease is caused by bacteria, you should administer an antibiotic treatment (Maracyn, Tetracycline, or Seachem Paraguard);
  • If the disease is a result of a fungal infection, treatment should involve fungal medication;
  • A 20-50% water change is required in the home aquarium.

4.  Velvet Disease

Velvet disease, otherwise known as Gold Dust Disease, is caused by the parasite Oodinium, which burrows itself into the body of your platy fish causing gold-colored cysts that can later erupt into lesions.


  • Small, gold-colored dots on the skin of your fish;
  • Bleeding lesions as cysts erupt, skin peeling off (advanced stages).

How to Treat Velvet Disease:

  • Immediate action is required (It’s highly contagious and hard to detect in its early stages);
  • Copper medication like Seachem Cupramin shows promising results;
  • Switch off any artificial lighting in the aquarium;
  • Perform a 70-90% water change once your platy fish no longer exhibit symptoms.

5.  Internal Parasite (Camallanus)

One common parasite that can affect the health of your platies is Camallanus. It can be cured by administering a round of antiparasitic medication.


  • Brown or orange colored worm sticking out from the anus of your platy fish.

How to Treat Camallanus:

  • 5-day treatment with Levamisole or Fenbendazole;
  • Substrate vacuuming and filter cleaning;
  • Major water changes upwards of 90%;
  • Repeat treatment after 3 weeks.

It’s more common in fish kept in outdoor ponds, but it can infect aquarium fish especially if said outdoor pond fish are moved indoors.

6.  Dropsy

Dropsy is the result of a bacterial infection that attacks the kidney or liver of your platy fish causing them to retain water. Once the liver or kidney is attacked, the disease is incurable.


  • Swollen belly;
  • Scales poking out of body;
  • Difficulty swimming.

The triggering factor of dropsy is bad water conditions, which can promote the proliferation of bacteria.

Platy fish affected by dropsy cannot be cured. You can help your fish relax or feel more comfortable by adding 2 tablespoon of Epsom salts for every gallon of water. The salt may draw out some of the excess water, but it won’t cure your platy fish.

7.  Ammonia/Nitrate Poisoning or Red Blood Spot Disease

If you notice blood red spots on the belly of your platy fish, you may be facing an ammonia or nitrate poisoning, which can be common in newly set up aquariums.


  • Red spots on your platy’s abdomen;
  • Black spots in case of ammonia burn.

How to Treat Red Blood Spot Disease:

  • If caught in its incipient stage, you may be able to save affected platy fish by refraining from feeding them for one day and performing a major water change.

As with other diseases in this list, it’s far easier to prevent the disease rather than treat it. Even in low levels, ammonia and nitrites are toxic to your fish.

Make sure you perform the nitrogen cycle properly and set up an ammonia monitoring device like the Seachem Ammonia Alert to help you keep an eye on ammonia levels.

8.  Viral Hemorrhagic Septicemia (VHS)

A virus that enters the bloodstream of your platy fish is the cause of VHS. If left untreated, it’s deadly for your fish.


  • Lesions on body;
  • Pale gills, bulging eyes;
  • Rotting fins;
  • Ulcers and darkening in color in later stages.

How to Treat VSH:

  • Antibiotics are the routine treatment for this disease, I recommend Maracyn 2, API Furan 2;
  • Antibiotic treatment should be followed by major water changes.

9. Pop-Eye

Unfortunately, it’s difficult to pin down a single cause for Pop-Eye disease. Bulging of the eyes can be cause by a variety of problems including poor tank conditions, fungal infections, dropsy, fish TB, internal parasites, bacterial infections, etc.


  • Eye protruding from socket, eye falling out in advanced stages;
  • Other symptoms specific to the underlying cause.

How to Treat Pop-Eye:

  • To apply proper treatment, it’s crucial to know what caused pop-eye disease. Bacterial infections require treatment with antibiotics, fungal infections require antifungal medication.

10. Hexamitiasis

A parasitic infection that’s not as common for platies, it can still find its way into your aquarium. Since it’s a parasite-caused disease, it can be eliminated with antiparasitic medication.


  • Discoloration of body;
  • Lesions or holes on head and/or body;
  • Loss of appetite.

How to Treat Hexamitiasis:

  • Treatment with metronidazole either by offering it in food if your platy will still take food, or if not, as a tank-level treatment.

Overstocked aquariums with low oxygen levels are the primary trigger factors of the disease.

11. Flukes

Advanced stages of the disease are incurable, however, caught early it can be treated. Flukes are caused by worms (parasites) that burrow themselves into the gills of your platy fish.


  • Difficulty breeding, fish seen swimming to the surface and gasping for air;
  • Bleeding gills in more advanced stages.

How to Treat Gill Flukes:

  • Advanced stages are incurable, if caught early, however, the disease can be treated with medication for gill flukes. Tank level treatment is required.

12. Fish Tuberculosis

Fish TB is an incurable disease that can be passed from fish to humans. It’s caused by mycobacterium.


  • Hollow belly;
  • Loss of appetite;
  • Fin and tail rot;
  • Inactivity;
  • Ulcers on body and around anus.

Because there is no treatment, sick fish should be removed and disposed of. Some aquarists report some success when administering treatment with Neomycin, Kanamycin or Isoniazid antibiotics.

Be very careful when handling fish infected with TB as they can pass the disease to you. Wear protective gear when handling diseased fish.

13. Bent Spine

Otherwise known as scoliosis, bent spine is a result of both genetic and environmental factors. Fish with this disease will have trouble swimming and will have a shorter lifespan.

Since it’s a genetic disorder, it cannot be cured. It can be prevented, however, by not allowing platy fish with deformities reproduce, avoiding inbreeding and offering them a balanced and healthy diet.


  • Crooked back that can be observed even in juveniles;
  • Difficulty swimming.

The good news is that the disease is not contagious, but it can be passed down to offspring, so reproduction should be prevented.

14. Mouth Fungus

Despite its name, this disease is caused by a bacterial infection (Columnaris). It can appear as a splash of white on the mouth or body of your platies.

It’s highly contagious and if left untreated it will paralyze the muscles of your fish rendering them unable to swim.


  • Whitening at the mouth or middle of the body;
  • Difficulty swimming;
  • Ragged fins;
  • Excess mucus production;
  • Lesions in advanced stages.

How to Treat Mouth Fungus Disease:

Treatment of the disease involves administering antibiotics, formalin, aquarium salt or potassium permanganate (KMnO4) dip bath.

You can administer Maracyn antibiotic or add aquarium salt to the water at 1 teaspoon per gallon dose for 3 days after performing a 50% water change.

After the 3 days of treatment, wait to see if symptoms improve, if your fish are cured, perform another water change at 50-70% rate.

Potassium permanganate is a powerful oxidizing agent and you must be very careful as it can burn your platies. Administer up to 10 ml/l in the dip bath and don’t leave the fish in for more than 30 min.

Platy Fish Disease Prevention 101

If you want to make sure diseases in your platy aquarium are kept at bay, there are a few things you can do to minimize the chance of disease.

While some of these things are second nature to many experienced aquarists, beginners may need to revisit this section of the article to better manage their disease prevention strategy.

Here are my top tips on how to prevent diseases in your platy aquarium:

1.  Complete the Nitrogen Cycle

It can take a couple of long weeks for the nitrogen cycle to fully complete and before you can add any fish to the aquarium.

A tank that is not cycled or it’s improperly cycled will not have beneficial bacteria that can break down harmful toxins into less harmful substances.

Therefore, when you set up a new tank, make sure you are familiar with the steps required to fully cycle your aquarium.

2.  Maintain Optimal Water & Tank Parameters

There’s good reason why your fish enjoy certain water parameters – these parameters will ensure that the biological and physiological functions of your platy fish are facilitated best.

Research the required water temperature, water pH, water hardness and other parameters like tank size, substrate and ideal environment for your fish.

See if your fish require a heater, filter or air pump and invest in quality equipment.

3.  Perform Regular Water Changes & Tank Cleaning

By changing the water at regular intervals and cleaning the tank, you’ll dilute accumulated toxins, debris and leftover food minimizing the chance of ammonia spikes.

The filter and the bacterial colony alone can’t sustain a healthy environment and regular water changes are needed to replenish the aquarium water with nutrients and oxygen.

4.  Don’t Overlook the Power of a Healthy Diet

A healthy and varied diet will help build a strong immune system that can put up a fight in the face of diseases. Don’t overfeed your fish. Overfeeding can cause constipation and increased waste production.

5.  Be Circumspect with What Your Introduce into the Aquarium

Adding new plants or decorations into the aquarium? Sanitize them first! They may carry parasites or protozoa that can make your fish sick.

Likewise, if you’re feeding your fish live foods, be careful where you buy them from as these too can carry diseases.

6.  Quarantine New Fish

If you’re adding new fish into your aquarium, make sure to quarantine them first and observe them for a week or two. If they seem alright and show no signs of disease, you can introduce them into the tank.

7.  Research Compatibility

Fish that don’t get along might fight, causing injuries that will lead to diseases and illnesses like secondary infections from the injuries sustained.

Even if your fish don’t fight but there’s tension between them or bullying, this too is a stress factor that can and will lead to health issues.

If you’re keeping more than one type of fish, make sure you get water conditions just right for everyone and make sure they’re compatible tank mates.

8.  Eliminate Stress Factors

Stress factors include overcrowded tanks, bad water conditions, noisy environment, too much or too little light, incompatible tank mates, and so on.

Make sure you have a large enough tank to house all inhabitants comfortably and that water conditions and environmental conditions are right for your fish.

Monitor water conditions, health status, and fish behavior for a better insight into their general wellbeing. Adjust water parameters and diet as needed.

These tips apply not only to platy fish keeping, but to any type of fish you’re raising.


I believe that by following the disease prevention guide I detailed above, you’ll be able to avoid fatal diseases that can affect your platy fish.

There are a handful of diseases that aren’t curable, and prevention is the only way to make sure your platies are out of harm’s way.

By keeping a regular tank cleaning and water replacement schedule coupled with disease monitoring and a healthy diet, you can offer your platies not only a good start in life, but you’ll also make sure they live a long and healthy life.

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