Fungus Disease In Fish, Diagnosis, And Treatment

Last updated on December 24th, 2022 at 11:06 am

Fungus Disease In Fish, Diagnosis, And Treatment in 2021

If your fish has white or gray growth in its mouth or body (often fluffy like cotton wool), a yeast infection may develop. Fungal outbreaks are usually caused by stressful conditions or low water quality and can quickly lead to secondary diseases. Hence, it is essential to address the problem immediately. This article covers different options for treating fungus as well as preventing them from returning.

If you see symptoms of illness, we always recommend a thorough cleaning of the aquarium first. We want to make sure the environment is optimal and stress-free for the fish before we start treatment. To quickly see the fish’s condition, rub the glass, clean the filter from dirt, and then vacuum the substrate with a siphon and change the water.

Fungi can often be prevented, so the next step is to find the cause of the infection. There is no point in treating the fish unless we stop causing the problem, as the fungus could strongly return.

What is a Fungus? 

Fungi are a diverse category of living things, and mushrooms are among the most well-known. People are sometimes confused with plants, although they are an entirely different species. Fungi are classified as a separate kingdom in taxonomic classifications.

Fungi do not photosynthesize like plants; instead, they absorb dissolved chemicals to ingest nourishment. To do so, they produce digesting enzymes.

The majorities are pretty tiny, and some are even single-celled, like Multicellular filamentous moulds, macroscopic filamentous fungus (mushrooms) and microscopic yeasts.

The majority of animals live on land, but others spend all or part of their lives in water. These are the types of fungus you could come across as an aquarist.

Species most commonly develop as hyphae string-like structures that can reach a few inches in length. To generate a branching effect, new hyphae grow from old hyphae.

This shape maximizes the organism’s surface area to volume ratio.

In natural ecosystems, fungi play a significant function. For example, in a food web, they are usually the primary decomposers. They decompose organic materials, which is an essential component of many nutrient cycles.

In an aquarium, though, they might create health issues for your fish. So it’s essential to consider this kingdom of creatures so that you can assist your fish if they have fungal infections.

What causes fungus in fish?

Low water conditions are a common cause of yeast infections. We see a lot of Betta fish with this disease because they are often kept in tiny containers with no heating or filters. Bettas like temperatures between 78 and 80 ° F means they will need heating if the temperature in their room is below that range

It also helps keep them in an aquarium that can hold at least 5 gallons or more to prevent their litter from getting into the water quickly. Regular partial water changes and adding live plants (especially floating plants) to an aquarium can remove toxic waste before it harms the health of your betta fish.            

Nutritional deficiencies can be another reason fish get mushrooms. Like humans, fish need a balanced diet to be healthy enough to fight disease. If you always feed the fish with the same flake glass, you will only provide one person hamburgers each day.

Of course, they can survive, but their bodies are likely not in perfect shape. So make sure you a) provide a wide variety of foods to get all of the essential nutrients and b) feed them fresh, quality foods. Yes, the container’s expiration date can indicate that the food can be kept for another three years.

Every time the box opens, it takes in more air and moisture, so the food is stale within months. If you don’t have enough fish to finish the jar in no time, divide the food into smaller sachets and freeze it to keep it fresh until you’re ready to use it. Lastly, avoid using wet fingers to remove food from the container as it can cause mold growth, leading to fungus or other diseases.  

Many live porters such as guppies and fancy mollies often develop fungal infections shortly after being brought home from the pet store.  Cement tank “with less activity and competition.     

Fish Fungus |

Causes of Fungal Diseases

In aquariums, potentially dangerous fungal spores are always present, but they generally go unnoticed since they don’t cause any harm. Poor water quality or sick fish are the two primary ways that these fungi can become an issue. Fungal spores proliferate fast when the water quality is poor. 

However, your tank’s poor conditions make it a breeding habitat for all diseases, not just fungus. This is one of the reasons why it’s so important to keep your fish in a healthy habitat. Because of its weaker immune system, a sick fish is more likely to get a fungal infection. This is why fungi are often found as a side effect of a more serious ailment.

Even stressed fish will have a harder time fighting illness. Physical wounds are most commonly caused by fighting, although they may also be caused by handling in a net, parasite infections, or bacterial infection ulceration.

Though certain fungal species will always be present in your aquarium, new fish or secondhand equipment may bring new species. As a result, quarantining is a good way of prevention, which we’ll explore later.

Fungal Disease In Betta Fish | Betta, Fish, Betta fish

How to get rid of mushrooms in fish?

If your fish’s mouth shows signs of fungus or rot, we recommend using Maracyn. Some bacterial infections (such as columnaris ) look like cotton growth or greyish-white patches around the mouth and must therefore be treated with an antibiotic. Before treatment:

  • Clean the aquarium and remove any chemical leaks (such as activated carbon or Purigen resin ).
  • Follow the manufacturer’s directions by measuring one sachet per 10 gallons of water and repeating it every 24 hours for five days.
  • Complete the full 5-day drug cycle even if symptoms seem to go away as the infection may still be present in the fish’s system.                                 

If the fungus is elsewhere in the fish’s body, use a combination of Maracyn and Ich-X. Ich-X contains formaldehyde, methanol, and malachite green chloride, which are effective against fungal infections. Before treatment, clean the aquarium and remove any chemical seepage.

Suppose the yeast infection is low; dose one sachet of Maracyn and one tablespoon of Ich-X coffee with 10 gallons of water. Let it sit for a full week and make sure the symptoms go away completely.

If symptoms persist or the yeast infection is severe at first, use one sachet of Maracyn and one scoop of Ich-X coffee with 10 gallons of water and repeat the dose every 24 hours for 24 consecutive days.

If you don’t have a planted aquarium or can get your fish into a quarantine pond with the wrong decor, salt is a great way to treat mouth and body fungus. You can use any form of sodium chloride (NaCl) table salt. However, for this article, we use aquarium salt or rock salt, not table salt, sea salt, or Epsom salt.       

After many years of the medicinal use of salt, we have found that most capercaillie, barbel, danios, African cichlids, live porters, fish, goldfish, shrimp, and even plecos can tolerate salt. However, other fish such as anchor catfish are susceptible and should never be exposed to salt.

Start with a low concentration of 1 tablespoon of salt per 3 gallons of water to ensure your fish can withstand the salt treatment. Once the fish has hardened after a week, gradually remove the salt through a series of 30% weekly water changes. If the mushroom is still active, you need to increase the concentration of salt. You can also use salt in conjunction with Ich-X to get a powerful punch against the fungus.

Will other mushroom medications work?

In our experience, herbal remedies for yeast infections are not very useful. Once the disease hits a fish, it will need more vital medication to save its life better. After many years of running a fish business and hundreds of customers helping Maracyn, I-X, and Salt are the treatments we have found to work best for fish mushrooms.

Ultimately, fungal spores will still be present in our aquariums, but full infections can usually be prevented. The key is to improve your fish’s health and provide them with a clean environment that is free from stress and the necessary nutrients they need to control.   


There is no guarantee that a fish can survive a fungal disease with treatment. There are several steps you can take to reduce the risk of an outbreak in your aquarium.   

health risks when owning fish

We mentioned earlier that an unhealthy environment allows pathogens to thrive and works very well in poor conditions. If you take good care of your aquarium, it will be much more difficult for fungi to infect your fish.   This includes regular partial water changes and removing excess algae.       

Use a water test kit every week. This will help you keep track of water chemistry. If the settings are not correct, you can correct them before the fish gets sick.      

Pathogens such as fungi can enter an aquarium every time you introduce new fish or used equipment into your aquarium. The quarantine can prevent this.   

Keeping new fish in a separate tank for some time will allow you to watch them for any signs of disease over time. They can then be added to your main tank once you are sure they are disease-free.   

When buying new fish from a store, check the inventory for signs of disease. If you see symptoms, buy elsewhere.   


Fungi are an extensive and diverse group of organisms. They play a crucial role in natural ecosystems, especially in the nutrient cycle. In an aquarium, however, it is different. You are a nuisance. They can suddenly spread quickly in the tank and cause illness that can be fatal.      

Although it looks dark, there are many things you can do to keep your fish safe.

Prevention is the first thing you can do while maintaining ideal conditions for your fish. Plan for the worst, but mushrooms on fish are sometimes inevitable. There are many different fungal diseases. If you think your fish has one, do some research. The most common conditions are easy to apply.      

For treatment to be most effective, you need to identify the problem early on. Therefore, keeping an eye on your fish is one of the best things to do.

Following the advice in this article will give your fish the best chance of survival.

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