How To Cure Fish Fungus (Aquarium Fish) Ultimate Treatment & Medication 2024

By: Martin McAdam
Updated: June 23, 2022

Fungal diseases are some of the most common infections in fish. It can be caused by several fungi and affect freshwater and saltwater fish. Fungal infections are often difficult to treat and can be fatal if not caught early.

There are a few things that you can do to help prevent your fish from getting fungal infections.

The best way to prevent fungal infections is to practice good aquarium maintenance. This means keeping your tank clean and free of debris. These precautions can help ensure your fish stay healthy and free of disease.

It is essential to learn about all diseases to be prepared to deal with them if they occur in your aquarium. Fish fungus is a common disease and one that every fish owner should be familiar with. This guide will teach you everything you need to know about fish fungus, including spotting the signs of an infection and treating it effectively.

What is a Fungus

Fungi are a large group of organisms, including mold, mildew, and yeast. There are many different types of fungi, and they can be found worldwide. Fungi thrive in moist environments and can often be found in soil, plants, or water.

While most fungi are harmless to humans, some can cause serious diseases. Fish are especially susceptible to fungal infections, as their bodies are covered in a thin layer of mucus that fungi can easily penetrate.

They are often mistaken for plants, but fungi are more closely related to animals. Unlike plants, fungi do not contain chlorophyll and cannot produce their food. Instead, they obtain nutrients by breaking down organic matter. Fungi are their kingdom, separate from plants and animals.

Fungi do not photosynthesize like plants; they get their energy from organic matter. This means they are decomposers and play an essential role in the environment by breaking down dead plants and animals.

Some fungi are parasitic, meaning that they live off of other organisms. Fish fungi are usually parasitic and can cause severe infections in fish.

Most are incredibly small; some are even invisible to the naked eye. Fungi release spores into the air. These spores can travel long distances and eventually land in an aquarium.

Once they find a suitable host, they will germinate or begin to grow. As they grow, they produce more spores, which can spread the infection to other fish.

Fungi are classified into two main groups: pathogenic fungi, which cause disease in fish, and saprophytic fungi, which do not. The vast majority of fish fungi are pathogenic, which can cause serious illness in fish.

The most common type of pathogenic fungus is Saprolegnia. This genus includes over 200 different species of fungi, many of which can infect fish. Saprolegnia is often called "cotton wool disease" because of the white, fluffy growths it produces on infected fish's skin.

Other common types of pathogenic fungi include Achlya and Aphanomyces. These fungi are often responsible for "ulcerative diseases," or open wounds, on fish's skin. Aphanomyces is a virulent fungus that can be fatal if not treated promptly.

Fungal infections are often difficult to treat and can be deadly if not caught early. It's so important to learn about the different types of fish fungi and how to spot the signs of an infection.

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Causes of Fungal Diseases

Potentially harmful fungal spores are constantly present in the environment. Usually, these spores do not threaten fish, as their immune systems can keep the fungi in check.

However, several circumstances can weaken a fish's immune system and make them more susceptible to infection. The most common cause of fungal disease is poor water quality.

Fungi thrive in moist environments and can quickly multiply in water high in ammonia or nitrites. This is why it's so essential to maintain clean, well-filtered water in your aquarium.

Another common cause of fungal disease is stress. Stressed fish are more likely to get sick as their immune systems are weakened. Stress can be caused by several factors, including bullying from other fish, inadequate water quality, and lack of food.

Injury is also a common cause of fungal disease. Fish with open wounds are more likely to get infected, as fungi can enter the body through these breaks in the skin. Physical injuries typically occur due to the fighting but can also be caused by rough handling or contact with sharp objects.

Though some fungal species will always be present in the environment, certain circumstances can cause a sudden outbreak. One of the most common triggers is a sudden temperature change.

Fungi reproduce best in warm, moist conditions. A sudden drop in temperature can cause the fungi to go into "hibernation" and stop producing spores. When the temperature rises again, the fungi will "wake up" and begin to reproduce.

This is why it's important to acclimate fish slowly when adding them to your aquarium. A sudden temperature change can cause a fungal outbreak and make your fish sick.

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Common Fungal Diseases

There are many different kinds of fish fungi, but only a few are commonly responsible for disease in aquarium fish. Some will only affect certain fish species, while others can infect any fish.

Regularly take the time to watch your fish, and look for any signs of illness. The sooner you catch a fungal infection, the easier it will be to treat.

The most common types of fish fungal diseases are:

Cotton-Wool Disease (Saprolegniasis)

This is the most common type of fungal disease in aquarium fish. It's caused by the genus Saprolegnia and is often called "cotton-wool disease" because of the white, fluffy growths it produces on infected fish's skin.

Cotton-Wool Disease

Cotton-wool disease typically affects fish that are already sick or injured. The fungi enter the body through open wounds and quickly begin to multiply. The infection can spread to healthy tissue and cause severe damage in some cases.

This disease is most commonly seen in freshwater fish but can also affect saltwater fish. It's prevalent in new aquariums or those with poor water quality.

The most common symptoms of cotton-wool disease are:

  • White, fluffy growths on the skin
  • Reddened or inflamed skin
  • Loss of appetite
  • Lethargy

If you notice any of these symptoms in your fish, quarantine them immediately and check the water quality in your aquarium. Poor water quality is the most common cause of cotton-wool disease, so it's essential to ensure that your tank is properly maintained.

Treat your fish with this disease with a commercial anti-fungal medication if you think that your fish have this disease. These are available at most pet stores and can be used to treat the infection.

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Gill Rot (Branchiomycosis)

Gill rot is a common fungal disease that affects freshwater fish. The genus Branchiomyces cause it and typically involves fish already sick or stressed.

Gill rot

This disease is much less common than cotton wool but can be just as dangerous. The fungi attack the fish's gills and can cause severe damage if left untreated.

The most common symptoms of gill rot are:

  • Labored breathing
  • Flashing (rubbing the body against objects in the tank)
  • Loss of appetite
  • Lethargy

Carp, pike, and tench aren't kept in home aquariums. But if you have any other fish type and notice these symptoms, check for signs of fungus on the gills. Your fish probably have gill rot if you see any white or fuzzy growths.

The disease produces mucus around the gills, making it difficult for the fish to breathe. The gills will become completely covered in some cases, and the fish will suffocate. The gills will gradually rot and decay, and the fish will die.

Treat your fish with gill rot with a commercial anti-fungal medication if you think that your fish have gill rot. These are available at most pet stores and can be used to treat the

Ichthyosporidium (Ich)

Ichthyosporidium is a fungus that can affect both freshwater and saltwater fish. It's caused by the Ichthyosporidium and is also known as "ich" or "white spot disease."

Ichthyosporidium

This disease is relatively rare but can be dangerous if left untreated. The fungus attacks the fish's gills and can cause severe damage.

First, it targets the fish's internal organs and moves to the gills. Its primary focus is the liver and kidneys, but it can also attack the heart and brain. The infection can cause the gills to become inflamed and swollen. The gills will become completely covered in some cases, and the fish will suffocate.

The most common symptoms of ichthyosporidium are:

  • White spots on the skin
  • Scratching (using the fins to scratch the body)
  • Flashing (rubbing the body against objects in the tank)
  • Loss of appetite
  • Lethargy

If you notice any of these symptoms in your fish, check for white spots on the skin. These tell-tale signs of ichthyosporidium can help you diagnose the disease.

If you think that your fish have this disease, treat them with a commercial anti-fungal medication. These are available at most pet stores and can be used to treat the infection.

Exophiala sp. (Exophiala Dermatitidis)

Exophiala sp. is a fungus that can affect freshwater and saltwater fish. It's caused by the genus Exophiala and is also known as "black spot disease."

Exophiala Dermatitidis

This disease is relatively rare but can be dangerous if left untreated. The fungus attacks the fish's skin and can cause severe damage.

Two species in the genus Exophiala cause disease in fish: Exophiala dermatitidis and Exophiala salmonis. These fungi are often found in freshwater streams and rivers and can be transferred to aquariums through infected fish.

The most common symptoms of exophiala sp. are:

  • Black spots on the skin
  • Flashing (rubbing the body against objects in the tank)
  • Loss of appetite
  • Lethargy

If you notice any of these symptoms in your fish, check for black spots on the skin. These tell-tale signs of exophiala sp. can help you diagnose the disease.

Treat your fish with this disease with a commercial anti-fungal medication if you think that your fish have this disease. These are available at most pet stores and can be used to treat the infection.

Egg Fungus

Fish eggs are at risk of infection from several different fungi. The most common are Aspergillus, Penicillium, and Rhodotorula. These fungi can enter the egg through the shell and infect the embryo.

Egg Fungus

The most common symptom of egg fungus is a white or fuzzy growth on the egg's surface. This growth is usually visible to the naked eye and can be seen with a magnifying glass.

Damaged or infertile eggs are the most susceptible to fungus, as they are more likely to have cracks in the shell. If the egg is fertilized, the fungus can infect the embryo and kill it.

Remove the affected eggs from the tank if you notice this symptom in your fish eggs. These eggs will not hatch and can infect the other eggs in the tank.

To prevent egg fungus, keep the tank clean and free of debris. This will help to reduce the chances of the fungus spores entering the tank.

You can also use a commercial anti-fungal medication to treat the eggs. These are available at most pet stores and can be used to prevent or treat egg fungus.

Treatment & Medication

We have now reached the treatment section of this complete guide to fish fungus. As we have already seen, several different types of fungi can affect fish.

If you think your fish have a fungal infection, the first thing you should do is to check for the symptoms. This will help you identify the fungus type and choose the most appropriate treatment.

If unsure of the diagnosis, you can always take a sample of the affected tissue to your local vet or fish store. They can identify the fungus and recommend the best course of action.

Once you have identified the fungus, you can treat it with a commercial anti-fungal medication. These are available at most pet stores and can be used to treat a variety of fungal infections.

It is essential to follow the instructions on the packaging, as each medication is different. Some medicines will need to be added to the water, while others will be added directly to the food.

It would help if you also quarantined any fish infected with a fungus. This will help prevent the spread of the disease and allow you to treat the fish more effectively.

To quarantine your fish, set up a separate tank for them. This tank should be well-filtered, and you should not add any other fish to it.

It would help if you also increased the water temperature, as this will help speed up the treatment process. The optimum temperature for treating fungal infections is 77-82 degrees Fahrenheit (25-28 degrees Celsius).

After treating your fish, you should keep a close eye on them. This will help you identify any further symptoms and allow you to take action if the infection does not clear.

If the infection does not clear up, you may need to increase the dosage of the medication or change to a different type of medication. You should always consult your vet or fish store before doing this, as they will be able to advise you on the best course of action.

Prevention

There is no guarantee that you will be able to prevent your fish from getting a fungal infection. However, there are several things you can do to reduce the chances of this happening.

The first thing you should do is to keep your tank clean. This will help reduce the chances of the fungi spores entering the water and make it easier to spot any early symptoms of an infection.

You should also quarantine any new fish that you add to your tank. This will help prevent the spread of disease and give you the chance to treat any infections before they have a chance to take hold.

It is also good to use a commercial anti-fungal medication in your tank. This will help kill any fungi that are present and help prevent new infections from taking hold.

You should also ensure that your tank's water is at the correct temperature. As we have already seen, some types of fungi thrive in warm water. Keeping the water at a cooler temperature makes it harder for the fungi to survive.

Finally, you should avoid overfeeding your fish. This can lead to a build-up of waste in the tank, creating the perfect conditions for a fungal infection to take hold.

Summary

Fungi are a huge and varied group of organisms. Some fungi are beneficial, while others can cause disease in fish. The most common type of fish fungus is Saprolegnia, which can cause several different symptoms in fish.

If you think your fish have a fungal infection, you should check for the symptoms and then take a sample to your local vet or fish store. Once you have identified the fungus, you can treat it with a commercial anti-fungal medication.

You should also quarantine any fish infected with a fungus and increase the temperature of the water.

If the infection does not clear up, you may need to increase the dosage of the medication or change to a different type of medication.

There is no guarantee that you will be able to prevent your fish from getting a fungal infection. However, there are several things you can do to reduce the chances of this happening.

Fungal infections can be challenging to treat, but most fish will fully recover with the proper treatment.

Following the advice in this article can help keep your fish healthy and free from disease.

Disclaimer

AquaMarinePower.com does not intend to provide veterinary advice. We go to great lengths to help users better understand their aquatic friends. However, the content on this blog is not a substitute for veterinary guidance. For more information, please read our disclaimer.

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