Bacterial Gill Disease in Bettas: Causes, Symptoms, and Treatment

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By Linh Nguyen Updated on 02 Feb 2023

It's no secret that bettas make popular and engaging pets. However, like all other types of fish, bettas are susceptible to illness if not cared for properly.

Bacterial gill disease is one of the most common respiratory diseases in fish. It is caused by a wide variety of bacteria, including Aeromonas, Pseudomonas, and Vibrio species. These bacteria cause inflammation and damage to the delicate tissues of the gills, resulting in difficulty breathing and often death.

In this blog post, we'll cover what causes it, how to treat it, and how to prevent it from happening in the future. So if you're a betta owner, be sure to read on!

Bacterial gill disease in bettas

Bacterial gill disease in bettas

1. What is bacterial gill disease betta?

Bacterial gill disease in betta fish is caused by several different bacteria. The most common cause is Flavobacterium columnaris, also known as Flexibacter Columnaris. This bacteria is often found in stagnant or slow-moving water and can infect bettas through their gills. Another common bacterium that causes bacterial gill disease is Pseudomonas aeruginosa. This bacteria is commonly found in dirty or contaminated water and can enter a betta's body through its gills or open wounds.

Symptoms of bacterial gill disease include increased mucus production, difficulty breathing, and lethargy. If left untreated, bacterial gill disease can be fatal to bettas. Treatment for bacterial gill disease includes antibiotics and regular water changes.

2. Causes

Bacterial gill disease is a common ailment in betta fish and is caused by a number of different factors. Poor living conditions such as overcrowded tanks, poor water quality, increased water temperature, or increased ammonia levels, are often the primary culprits. Additionally, too many leftovers and organic debris can also lead to bacterial growth and infection.

Crowded tanks: Overcrowding can lead to an increase in stress levels and a decrease in water quality, which can allow bacteria to flourish. 

Poor water quality: Bacteria can proliferate in dirty water due to the presence of nutrient-rich organic matter. Ammonia and other toxins can also build up in poorly-maintained tanks, further harming fish. 

High temperatures: Warm water temperatures can cause bacteria to grow more rapidly, increasing the chances of fish becoming infected. 

Increased ammonia levels: Ammonia is toxic to fish and can cause gill damage, making fish more susceptible to infection.

A dirty fish tank

A dirty fish tank

3. Symptoms and pictures

Betta fish infected with a bacterial gill disease typically have difficulty breathing, as the gills are primarily affected. This can manifest in visibly rapid or labored breathing, and swimming close to the surface of the water as if trying to get air.

Additionally, they may show signs of a lost appetite and little to no eating. The gills themselves often show signs of swelling, redness within the gill tissue, and deformed gills. They may also have patchy growth of bacteria on them, which gives them a blotchy appearance. Without treatment, the gill and fin tissues will eventually deteriorate and necrotize.

Some betta fish may only exhibit mild symptoms of bacterial gill disease, while others may become very ill very quickly. If you notice any of the above symptoms in your betta fish, early diagnosis and treatment are essential for the best chance of recovery.

betta fish bacteria gills

4. Treatment

The recommended treatment for bacterial gill disease is a combination of potassium permanganate, aquarium salt, and antibiotics. In severe cases, the betta fish may need to be isolated in a hospital tank with clean, fresh water. It is important to monitor the betta fish closely during treatment and to make sure that the water quality in the tank remains good.

Potassium permanganate is an antimicrobial agent that is effective against a wide range of bacteria, including Flavobacteria. Aquarium salt helps to reduce stress and promote healing, while antibiotics help to clear the infection.

To treat Flavobacteria with potassium permanganate, mix 1 teaspoon of potassium permanganate with 1 gallon of water. This solution can be used to treat both fresh and saltwater bettas. For best results, soak the betta in the solution for 20-30 minutes per day for 5-7 days.

Aquarium salt should be added to the fish tank at a rate of 1 tablespoon per 5 gallons of water. The aquarium salt should be dissolved in water before adding it to the tank. Once added, the aquarium salt will remain in the tank indefinitely and does not need to be replaced.

Antibiotics should be administered according to the directions on the package. It is important to finish the entire course of antibiotics, even if the symptoms have cleared up. Stopping early may allow the infection to return.

In addition to the above treatments, it is important to keep the betta's tank clean and free of debris. Perform regular water changes and vacuum the gravel to remove any build-up of waste. A clean and well-maintained tank will help the betta heal more quickly and reduce the risk of relapse.

treatment of bacterial gill

5. Is bacterial gill disease contagious?

Yes, bacterial gill disease is contagious. It can spread from fish to fish through contact with contaminated water. Gill tissue is very delicate and easily damaged, so even a small amount of bacteria can cause an infection. If you see one fish with bacterial gill disease, there's a good chance that others in the tank are also infected. Treatment should be done as soon as possible to prevent the spread of the disease.

Prevention of bacterial gill disease can be achieved by maintaining good water quality and avoiding overcrowding in tanks. regular water changes and using a filter are also important in preventing this disease.

Here are detailed instructions.

6. Prevent

Bacterial gill disease in bettas is preventable. There are a few things you can do to help prevent this disease: 

  1. Keep your betta's tank clean. This means doing regular water changes and making sure that there is no build-up of waste or debris in the tank. 
  2. Don't overfeed your betta. Make sure you are giving them the appropriate amount of food and not overfeeding them. 
  3. Choose high-quality food for your betta. Some foods are better than others when it comes to preventing disease. Choose a food that has been specifically designed for bettas and that contains high-quality ingredients. 
  4. Quarantine new fish before adding them to your betta's tank. This will help to prevent the spread of disease. 
  5. Keep your betta's tank warm. Bettas are tropical fish and prefer warm water. Keeping the water too cold can stress them out and make them more susceptible to disease.

If you follow these simple steps, you can help keep your betta healthy and free from bacterial gill disease.


Bacterial gill disease is a common problem among bettas. While it can be treated, it's important to understand the causes and symptoms so you can prevent them from happening in the first place. Let me know in the comments below if you have any questions about bacterial gill disease or how to treat it. I'm happy to help!

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