Black Molly With White Fungus – All You Need To Know

It’s frustrating when a pet is sick, especially if you don’t know what it is and what you can do to help. Unfortunately, the same can happen to your black molly.

One of the most common diseases for these fish is white fungus. But no need to worry as it doesn’t affect your molly fish seriously.

Knowing the condition’s causes will allow you to know what to do to improve it. So, we will cover the causes and treatment of white fungus.

Let’s dive into this article to get it clear!

Why did your black molly get White fungi?

The leading cause could be your molly getting sick because of poor water quality, injury, open wound, overfeeding, weak immunity, or lack of nutrition.

Unclean Water

Contaminated or unclean water is one of the leading causes of your molly fish being infected with a white fungus. It is okay to test your water quality with one tester that you can easily find on eBay or Amazon.

Decorations Utilized

Fungi can also enter your beautiful aquarium through your decorations. It can quickly grow on gravel, wood items, and decomposed or dead plants.

Rotten and Uneaten Food

Overfeeding your fish will result in your aquarium being full of uneaten food.

So if you don’t regularly change the water and clean your aquarium regularly, the fungus will soon grow on the uneaten or rotten food.

Fungal infections spread quickly, so your black molly fish will soon catch it too.

New Molly Fish in Your Tank

Sometimes the source of a white fungal infection comes from your new molly fish. Therefore, we recommend isolating your new black molly in a separate tank before releasing them into your main aquarium.

Poor Nutrition or Immunity

Your black molly fish can also suffer from white fungus due to poor immunity and nutrition.

If you do not provide the proper diet, keep them in a stressful environment, or take care of them improperly, these animals are susceptible to white fungus.

Injuries And Open Wounds

Your mollies can be infected with a white fungus if these animals have injuries and open wounds. In this case, it is easy for viruses, fungi, and bacteria to infect your mollies’ bodies.

white fungus on black molly


How Do You Get Rid of White Fungus on Fish?

Isolate Sick Molly

When you find an infected molly, you must isolate it in another tank. Then give it a salt water bath as a safe and natural treatment to treat the fungus.

We recommend adding one teaspoon of salt to every five gallons of water.

Apply Anti-Fungal Method

You can purchase an antifungal treatment, which you can easily find at your local pet supply shop to treat fungus on your fish.

Using Hydrogen Peroxide or Methylene Blue is okay to treat white fungus on your black molly.

Vinegar will also help treat the water to prevent the fungus from spreading.

Provide the Right Nutrition

Providing the proper care is also one of the ways to ensure your fish quickly recovers from fungal treatment. A robust immune system will allow them to fight white fungus effectively.

Get Help From A Vet

Getting help from a trusted veterinarian for severe fungal infections is best. He will conduct a diagnosis and suggest the proper treatment for your black molly.

couple of black molly

How To Prevent White Fungus In Fish Tanks?

Preventing fungus from occurring is always a priority. Here are some tips that will allow you to minimize the spread of fungus in your mollies.

Clean Your Aquarium Frequently

You need to clean your aquarium regularly to prevent the fungus from spreading.

We recommend cleaning your aquarium every few weeks to prevent it from collecting dirt, dust, and other impurities.

Maintain The Optimum Water Condition

It is advisable to test the water in the tank regularly to ensure that ideal water conditions are maintained for your fish.

Water for this species is best with a temperature between 68 and 82 degrees Fahrenheit, a pH level ranging from 7 to 8 with an ammonia level of 0ppm.

Ideal conditions for white fungus growth are low water temperatures which are also unsuitable for black mollies.

Change Water Regularly

We recommend changing 25 to 50% of the water in the tank about three times a week or 10% every day to maintain a fresh and clean water supply.

Clean Your Water Filters

You should clean your aquarium’s water filter monthly or weekly to keep the air circulating clean and consistent.

Clean Tank Decor/Accessories

It is wise to wash your aquarium accessories, such as gravel and live plants, twice a week to minimize white fungus growth.

Avoid Overfeeding

After a few feedings, reduce the amount of food if you find a lot of uneaten food in your aquarium.

The white fungus can grow on leftovers and then spread to your black mollies.

Quarantining New Mollies

It is always best to isolate new mollies in other tanks for about 30 days before adding them to your common tank.


Why Is My Mollies Color Fading?

Your fish’s fading color could be a sign of severe stress. Stress can be caused by poor water quality, disease, over-cleaning of the tank, inappropriate or poor nutrition, overcrowding, being moved, and many other situations.

Will Fish Fungus Go Away by Themselves?

The fungus will not go away on its own. Instead, it needs to be treated.

The fungus can spread quickly, leaving your fish vulnerable to secondary infections, such as fin rot. It can also kill a fish if left untreated.

May White Fungus Make Mollies Sick?

Everything will be fine if you handle this situation in time. If you leave it for too long, it can be dangerous to your mollies.

For example, it can develop other bacterial infections, causing your fish to die if left untreated.


There are many reasons why black molly is infected with a white fungus. Take care of this situation as soon as possible before it seriously harms your fish!

If you have any queries, let us know via the comments section!

Thank you for reading!