Betta Fish Fin Rot: What Is It, How to Treat, and Prevention Tips

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By Linh Nguyen Updated on 01 Feb 2023

Betta fish are one of the most popular fish kept as pets in the world. They are beautiful and come in a wide variety of colors and patterns. If you've ever been around a betta fish, you've noticed their beautiful tails. But what happens when that flowing tail starts to look ragged and unhealthy? You may be dealing with betta fish tail fin rot. This condition can be alarming, but it does not always cause panic. In this article, we'll discuss what causes betta fish tail fin rot, how to treat it, and tips for preventing it from happening in the future. 

A betta fish with tail rot disease

A betta fish with tail rot disease

1. What is fin rot in betta fish?

Tail rot is a serious condition that can kill your betta fish if left untreated. It is characterized by the deterioration of the tail tissue, which eventually leads to the tail falling off. Tail rot is usually caused by infection, but it can also be brought on by physical trauma or poor water quality.

Tail rot is caused by a bacterial infection, and it can quickly spread to other parts of the fish's body. There are many different bacteria that can cause tail rot in betta fish, but the most common ones are Aeromonas hydrophila and Pseudomonas Aeruginosa.

Both of these bacteria are commonly found in stagnant or dirty water, and they can quickly infect a fish if its immune system is weak. Tail rot is often fatal in betta fish, so it's important to catch it early and treat it immediately.

2. What causes fin rot in bettas?

One of the most common causes of fin rot is poor water quality. Bettas require clean, well-oxygenated water in order to stay healthy. If the water they live in is dirty or stagnant, it can put them at risk for developing infections like fin rot. Another common cause of fin rot is injuries. If a betta sustains an injury to its fins, it can open up the tissue to bacterial infections. Lastly, stress can also lead to fin rot. Bettas that are stressed out due to poor living conditions or lack of food are more likely to develop diseases like fin rot.

Besides, there are a number of other causes that also cause betta fish to have fin rot including:

  • Overcrowding
  • Inadequate filtration
  • Parasites
  • Bacterial infection
  • Fungal infection
  • Nutritional deficiencies
  • Use of certain medications (such as antibiotics)
  • Genetics (some bettas are more susceptible than others)
A dirty fish tank

A dirty fish tank

3. Betta fin rot symptoms

Fin rot in bettas is a relatively common disease, and unfortunately, it can be quite serious if left untreated. The good news is that, with prompt treatment, most bettas will make a full recovery. There are three main stages of fin rot: early, moderate, and severe. Below are signs to identify fins in betta.

3.1. Early signs

The early stages of fin rot may not be all that noticeable. You might see a slight change in the coloration of the fins or a small amount of fraying at the edges. Some common symptoms include:

  • The edges of the fins appear ragged, frayed, or torn.
  • The tips of the fins may turn white, black, or brown.
  • The fins may appear to be melting away.
  • The fish may scratch itself against objects in the tank.

If you notice any changes in your betta's fins, it's important to take action right away. The sooner you start treatment, the better the chances of a full recovery.

A betta fish with early stage tail rot disease

A betta fish with early stage tail rot disease

3.2. Moderate stages

If fin rot is left untreated, it will progress to the moderate stage. At this point, the fins will become increasingly damaged and discolored. You may see large chunks of tissue missing, and the fins may start to disintegrate. The fish will also become more susceptible to infection and predation. Specific symptoms include:

  • The fins are completely disintegrated, leaving only stumps.
  • The fish may stop eating.
  • The fish may become lethargic and listless.
  • The fish may hide away from other fish in the tank.
  • The fish may develop open wounds.

3.3. Severe stages

If fin rot is left untreated, it can progress to a severe stage. At this point, the fins will be completely damaged and may even disintegrate. The fish will also be more susceptible to infection and predation. In severe cases, the fish may even die.

  • The fins and tail are completely disintegrated.
  • The body is covered in open wounds.
  • The fish may stop eating and become lethargic and listless.
  • The fish's immune system may be compromised, leading to secondary infections.
A betta fish with severe tail and fin rot disease

A betta fish with severe tail and fin rot disease

4. Treatment

Fortunately, there are a number of effective treatment options for fin rot in bettas. The most important thing is to act quickly and get started on treatment as soon as possible.

4.1. How to fix fin rot in bettas in the early stage?

If you notice your betta's fins are beginning to look ragged or frayed, this is a sign of fin rot.

  • Begin treating immediately by doing a large water change, at least 50%.
  • Vacuum the gravel well to remove any decaying matter that might be contributing to the fin rot.
  • Add aquarium salt to the water, at the rate of 1 tablespoon per 5 gallons of water. This will help to discourage further bacterial growth.
  • Continue to do daily water changes until the fins begin to regrow and look healthy again.

You can read the article: A detailed guide to using aquarium salt to treat fin rot in bettas.

If your betta doesn't show signs of healing after 4 to 5 days, you'll need to take stronger measures to treat fin rot.

Aquarium Salt

Aquarium Salt

4.2. Cure fin rot in a moderate stage

Step 1: First, remove your sick fish from the tank. 

Start by removing the affected fish from the tank and placing him in a separate tank with clean, fresh water. This will help to prevent the spread of bacteria and allow you to treat the fish without harming others in the community. Help to prevent the spread of disease to the other fish.

Step 2: Check your fish’s environment.

Whenever your fish gets sick, it's important to find out why. Checking the water parameters with an aquarium water test kit is a good place to start. You can pick up water testing kits at most pet stores which will help you to analyze the pH levels and potential contaminants. The test should give you more information about the ammonia and nitrate levels. 

Make sure there are no environmental factors causing stress to your fish, like an overly strong filter, sharp decorations, or the wrong temperature. Use a thermometer to check the temperature. You will need to increase the water temperature to 83 - 86 degrees Fahrenheit (28 – 30 degrees celsius). This will help kill the bacteria that are causing the infection.

By taking these steps, you can help ensure a healthy environment for your fish and prevent future sicknesses.

Step 3: Recovering fish tank from infection.

Wash the tank and all its accessories thoroughly with hot water to kill any bacteria present. You can use a small brush or a sponge to help with the cleaning

If you have any live plants, it's best to soak them in lukewarm water before putting them back in the tank. You can then take them out of the water and let them air dry. Once you've washed the tank thoroughly and let it air dry, fill it with dechlorinated or conditioned water. Then, you can place the gravel and tank accessories back into the tank.

Step 4: You need to increase the aeration in the tank. 

Tail rot is a common bacterial infection in fish that can be difficult to treat. One way to increase the success of treating tail rot is to increase the aeration in the tank. 

Aeration helps to keep the water moving and prevents stagnation, which can allow the bacteria to grow. It also helps to oxygenate the water, which can help to kill the bacteria. The increased aeration will help oxygenate the water and promote healing. Increasing aeration can be done with an air pump or by simply adding more plants to the tank.

Step 5: Use salt and methylene chloride to treat fish.

Salt and methylene blue are two common treatments for fish diseases. Salt is a natural disinfectant that can help to kill bacteria and other organisms that may cause disease. Methylene blue is an antimicrobial agent that can help to prevent the growth of bacteria and other pathogens. These two substances can be used together to treat a variety of fish diseases.

To use salt and methylene blue to treat fish diseases, mix one tablespoon of salt with one cup of water (1 Tbsp salt per 3 Gallons of Water) Add this mixture to a clean container and add the methylene blue. Stir well and add the fish to the container. Make sure that the fish are completely covered by the mixture. Keep the fish in the salt solution for 4 to 5 days, and may increase the concentration if there’s no improvement.

Read more: A detailed guide to the use of methylene blue for the treatment of fin rot in bettas.

Instructions for using Methylene blue to treat betta fish

4.3. Prevent fin rot in a severe stage

When fish show signs of serious bacterial infection, such as respiratory failure, lethargy, loss of appetite, or skin lesions, you should use fish antibiotics. Antibiotics will help to clear up the infection and make your fish feel better.

Some aquarists use erythromycin to treat bacterial infections in their fish. This includes diseases like fin rot& tail rot as the antibiotic is effective against a wide range of bacteria. Erythromycin is available over the counter in powder form. To treat your fish, simply follow the instructions on the packaging to provide the appropriate dosage.

Most fish diseases can be treated with antibiotics, but it is important to use them correctly. Overusing or misusing antibiotics can create antibiotic-resistant bacteria. This means that the bacteria are no longer killed by the antibiotic and can continue to infect other fish.

Read more: Detailed instructions on the use of antibiotics to treat fin rot in betta fish.

5. How to identify fins rot in betta is getting better?

If you notice that the white edges around your fish fin are disappearing, this may be a sign that the fin rot is improving. You may also see signs of the tail regrowing. For a period of 2 to 4 weeks, your fish’s fin and tails should grow back fully.

They should start to look better, with less raggedness and a more healthy appearance. If there was any dark discoloration in the fins, they should be turning back to their original color.

6. Do fins grow back after fin rot?

It is possible for betta fins to regrow after being affected by fin rot, but it usually takes a while. New growth may not be as strong or as healthy as the original fins, and the betta may never regain full fins length. If you notice your betta's fins starting to show signs of rotting, it's important to act immediately to prevent further damage. You should clean the aquarium regularly and ensure the water quality is good, as this can help prevent the spread of infection.

7. Is fin rot contagious to other fish?

Tail rot is a serious infection that can affect bettas and other fish in the tank. Tail rot is caused by a bacteria called Pseudomonas Fluorescens. This bacteria thrives in warm, stagnant water. It can be spread from fish to fish through contact with infected fins or water.

If you notice any of these signs, It is important to treat the infection immediately and isolate the other fish in the tank from the sick betta fish. This will help prevent the spread of disease and protect the health of your fish population.

8. Can fin rot kill a betta?

Fin rot is a serious condition that can lead to the death of a betta fish. The infection causes the fins and tail to rot away, leaving the fish vulnerable to predators and unable to swim properly. In some cases, the infection can also spread to the body, causing even more damage. If left untreated, fin rot can quickly kill a betta fish. That’s why it’s important to watch for signs of the infection and get your fish to a vet or experienced aquarium owner as soon as possible. With prompt treatment, many bettas make a full recovery from fin rot.

Fin rot can kill your betta

Fin rot can kill your betta

9. How long does it take for fin rot to kill a betta?

In aquariums with poor water quality or where fish are overcrowded, fin rot spreads more quickly. Within 24 hours, you should see the wounds on their tails spreading, infected, and possibly some tail branches that have fallen off. Tail rot can spread quickly in tanks and bettas usually die within 4 - 5 days of infection.

If you suspect that your fish may have fin rot, it is important to act quickly. The sooner you identify and treat the problem, the better your chances are for the fish to make a full recovery.

10. How to prevent fin rot, tails rot in betta

Once tail rot has been treated and your fish is on the road to recovery, there are a few things you can do to help prevent it from happening again in the future.

One way to prevent fin rot in betta fish is by maintaining clean water conditions. This means performing regular water changes and keeping the tank free of debris. Another way to prevent fin rot is by providing your betta with a nutritious diet. A healthy diet will help boost your betta's immune system, making them less susceptible to disease. Here are some tips to keep in mind to prevent fin rot in bettas.

  • Maintain proper water quality. 
  • Make sure to clean the tank regularly.
  • Don't overfeed your betta. 
  • Avoid sudden changes in water temperature.
  • Void stressors such as loud noises or sudden changes in temperature.
  • Change the way your fish tank is set up.
  • Quarantine new fish.
  • Keep an eye out for early signs of fin rot.

Fin and tail rot disease in betta fish progress very quickly, if not detected and treated promptly, your fish will most likely die. However, this disease can be prevented and prevented early, so read article 11 causes and ways to prevent fin rot and tail rot in betta fish for more necessary knowledge.

Clean living environment helps prevent fin rot disease

Clean living environment helps prevent fin rot disease


Fin rot and tail rot are serious conditions that can quickly lead to the death of your betta fish. If you notice any signs of fin rot, it is important to take action and treat your fish as soon as possible.

The good news is that there are many treatments available that can be performed at home, but the most important thing is to catch it early and get started on treatment right away. We hope that one of these treatments will help clear up the infection and get your betta back to his healthy self in no time!

Besides, we also hope that the information provided has been helpful and informative. If you have any further questions or would like more advice on how to prevent or treat fin rot and tail rot in your betta fish, please let me know in the comments below!

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