Oscar Fish White Fungus: Causes & Treatments

The freshwater Oscar fish are incredibly well-liked among aquarium enthusiasts. They are gorgeous and entertaining to watch because of their mannerisms.

If you do decide to keep these pets, there are a few things you should think about, especially health issues like Oscar fish white fungus.

This post will discuss the causes, signs, and treatments of this bacterial infection. Let’s scroll down to get into details!

Oscar Fish White Fungus: Common Causes

An aquarium also includes good and bad bacteria. The fish do not suffer danger from harmful bacteria as long as they are healthy.

If you see white fungus in your tank, here are some of the leading reasons:

Water Quality Issues

Oscar fish are more prone to have fungus if the tank water is of poor quality.

Failure of the upper fin and filter may be the culprit, allowing parasites and illness to enter your tank.

Although your tanks often have an active filter, the filtration system can only turn organic wastes into less harmful compound nitrate.

The water quality decreases if you don’t replace it frequently enough. Your pets might get anxious and susceptible to fungal infections when the water is so bad.

swimming oscar fish

Water quality issues

Protozoan Infection

Although there are many other potential explanations for the white fungus on Oscars, germs and parasites are the most common culprits.

This illness is brought on by the freshwater and saltwater-found protozoan Ichthyophthirius multifiliis.

This white parasite infects and lives on your pets, which explains your question: Why is my oscar turning white?

Fish dwelling in close quarters, such as those in a tank or school, can spread the bacterium through the surroundings.


Stress, as previously mentioned, can weaken your Oscar’s immune system, which frequently presents an opportunity for germs to flourish.

Low water quality, bullying, crowding, or external influences like youngsters knocking on the tank or loud noises contribute to stress.


A crowded aquarium can soon develop issues with the water’s quality.

When you keep too many Oscars in one tank, the waste they generate might overwhelm the filtration system, causing the water quality to suffer.

Fish struggling for food or space and biting each other can also happen when the population is overcrowding.

It may result in injured or stressed pets becoming vulnerable to bacterial diseases.

Poor Diet

Due to their size and muscle, Oscars require a diverse diet to meet their dietary requirements.

The nutrient requirements won’t be content if you consistently give these creatures the same subpar flakes or pellets.

Without the right minerals and vitamins, Oscars may grow frail and vulnerable to bacterial illnesses.


Oscars sustain injuries when traveling or if other fish attacks or bully them.

The first line of protection these aquatic creatures have against germs is their skin. Bacterial infections may spread swiftly when that protection is broken.

white fungus oscar


Oscar Fish White Fungus: Typical Symptoms

You could see that the Oscars you own begin to get white patches on their skin.

These spots, which might seem like tiny lumps or lesions, can appear on your fish’s body.

The fish may eventually perish due to these white patches if they continue to spread and enlarge.

How do you know if your Oscar is dying? Consider the following symptoms:

  • Appetite loss
  • Breathing heavily
  • Change in scale color
  • Clamping fins on the body’s side.
  • Damaged, ripped fins
  • Frantic swimming
  • Abnormal trembling
  • Nervousness
  • Almost always hiding
  • Rubbing against the tank walls

Oscar Fish White Fungus: Treatments

How do you treat white spots on Oscar fish? Don’t worry! Below are some methods to save your pets:

Raise Temperature

By turning up the heat by roughly 2°F every three hours, you may quickly and effectively eliminate parasites while preventing the fish from suffering from a temperature shock.

The tomont parasites generate around 42percent less free-swimming theronts at an aquatic heat of 86°F compared to 77°F.

As a result, warming up a freshwater tank dramatically aids in treating fish suffering from bacterial infections.

Don’t be afraid when increasing the heat because your Oscars can withstand such high temperatures.

oscar fish in tank

Raise temperature

Increase Water Oxygenation

An inverse connection exists between a liquid’s temperature and the amount of air it can hold. It’s a good idea to vigorously aerate the tank water to prevent fish from shocking when the temperature in a tank is increased.

Some medicines will also absorb water’s oxygen. A powerful airstone is ideal for every 20 – 30 liters of water.

Add Aquarium Salt

It would be best if you determined how much salt is essential for the entire tank volume before adding it to a tiny portion of water in a different container.

Add the saltwater solution to your tank after stirring until all the salt dissolves completely.

If you want to learn more about aquarium salt before using it for your Oscars, it’s better to check this video:


Partially Change Water

If not specified differently in the medication’s directions, do a 25 percent water change for each dose.

To avoid shocking your pets during the water purification process, ensure the freshwater has the same temperature as the liquid in the tank.

Remove Chemical Filtration

Using activated carbon can eliminate any medicine in aquarium water. Remove this kind of material from your filtration system without turning it off.

Stop using UV purifiers as well, since they will make the drug useless by changing its molecules.

Treat Secondary Infections

Fish with the external parasite frequently have little open sores where the fungus is on their fins, skin, or gills.

It encourages more harmful bacteria or fungi, which may attempt to harm your pets in their vulnerable state.

It’s critical to keep an eye out for any reinfection in the injured Oscars and to administer the appropriate care.

treating your oscar

Treat secondary infections

Use Medicine

If the above methods don’t work effectively for your fish, you can consider using medicine like Maracyn Oxy.

Wrapping Up

In general, Oscar fish white fungus is a common parasitic infection in this species. However, you can detect this illness easily with apparent symptoms.

It’s best to treat this disease once you’ve detected it immediately. Hopefully, you will be successful with our practical solutions.

If you want to know more about this bacterial infection, please leave a comment below. We’re happy to answer all. Thanks for taking the time to follow us!