Betta Fin Rot: Causes, Prevention & Best Treatments

Betta Fin Rot

The list of most common Betta diseases that Betta keepers are familiar with, includes Betta Fin rot. So, it’s really necessary for a Betta keeper to know everything about this disease.

Betta Fin Rot is a condition characterized by tattered and discolored fins. There are several reasons behind it, lots of proven medications, and some easy ways of prevention.

So, without further ado, let’s talk in-depth about Betta Fin Rot.

What Is Betta Fin Rot?

It’s a clinical condition where the fins of your Betta fish are damaged, ragged, or discolored. It’s an extremely common disease, but the good news is, it’s treatable. Betta Fin Rot can be the result of your poor water condition and poor immunity of your fish.

What Causes Betta Fin Rot?

It can be a difficult job to figure out the exact reason for Betta Fin Rot. A lot of factors can contribute to it.

Bacteria Or Fungus?

Many believe that Betta Fin Rot is caused by gram-negative bacteria. There are few different types of bacteria leading to fin rot. Few of them are related to human pathogens, like Pseudomonas and Vibrio.

But Betta Fin rot can also be caused by fungal attacks. Fungal Fin Rot is slightly different from the ones caused by Bacteria. Besides ragged fins, you will notice white dots on the edge of the fins.

Stress Can Be The Culprit

But these Bacteria are present in water bodies 24×7 and do not potentially harm the fish around them. So the main reason can be your fish’s immune system. A weakened immune system is vulnerable to antigens.

Increased stress levels and aging weaken the immunity of Betta Fish. An increased stress level combined with bad water quality and food habits can lead to weakened immune systems.

Poor Water Quality

Another prime factor is the environment. Poor water quality increases the risk of exposure to certain harmful Bacteria. Bacteria, viruses, and other parasites can be found in abundance in poor water containers. The fish kept in these poor environments are more prone to parasitic attacks.

Poor water quality can also cause decreased oxygenation, decreased metabolic rate, and make things stressful for your Betta. Harmful water parameters are:

  • Temperature below 76 degrees Fahrenheit.
  • pH range exceeding the range of 7 to 7.5.
  • Cloudy and dusty water.
  • Ammonia, nitrite, and nitrate level over 0 ppm, 0 ppm, and 40 ppm respectively.
  • Increased waste products.
  • Uneaten foods.

External Injuries Can Cause Fin Rot

Any external injury on the fins will lead to Fin Rot disease if you keep the fish in poor water quality. These injuries can be caused by:

  • If your Betta is wounded by other tank mates.
  • If it starts to bite its own fin and tail.
  • Collision with any decorating substance of the aquarium.
  • If the Betta starts fighting with its own reflection.
  • Sharp stones.
  • Powerful water filter.

Inconsistent Feeding Habit

Overfeeding and underfeeding can also lead to a weakened Immunity. It can be really stressful for your Betta and make it more prone to several diseases.

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Symptoms Of Betta Fin Rot

The symptoms are quite noticeable in the later stages. But it’s really important to diagnose Fin rot at an early stage. Its prognosis can be classified into three stages:

  1. Mild fin Rot.
  2. Moderate Fin Rot.
  3. Severe Fin Rot (Body Rot).

Symptoms Of Mild Fin Rot

  • Pectoral, dorsal, and/or caudal fins with receding or disheveled edges.
  • The sides of the fins have a red pepper or brownish appearance.
  • White stains or a whitish hue around the fins’ margins.

Symptoms Of Moderate Fin Rot

  • You will notice the fins getting partial or total deterioration.
  • Fins that are black or blood-red in color and have visible tissue loss around the edges as they move towards the body.
  • The mushy formation will be seen mostly on fins’ ragged edges. it won’t appear in the body/head.

Symptoms of Severe Fin Rot

  • Fin degradation extends more than midway to the body
  • The complete loss of fins or the tissues in between fins’ rays.
  • The root of the fin nearest to the body will be swelling, bleeding, or blackish brown.
  • Scale loss and broken skin on the areas of the body nearest to the affected fins
  • From fins, the whitish mushes will grow towards the body or head.
Betta Fin Rot treatment

Treating Betta Fin Rot

If diagnosed at an early stage, Betta fin Rot can be treated successfully. The treatment procedures depend on the prognosis of the disease. You have to take different measures for each stage of Fin rot.

The key to preventing Betta Fin Rot lies in maintaining pristine water conditions. Mary McCauley of Mary’s Magic Bettas emphasizes the importance of regularly checking water parameters with a reliable test kit.

She suggests keeping ammonia and nitrites at 0 and nitrates below 20ppm. Additionally, incorporating natural tannins through Indian Almond leaves or Alder Cones can be beneficial.

In cases of severe infection, while medical intervention is sometimes necessary, Mary advises careful use of medications and consulting experts for guidance.

Treatments For An Early Stage Fin Rot

After understanding Betta’s condition, if you install a radiator, minimize the decorations or number of bettas, and raise the number of water changes, your betta might improve without any need for additional care. However, if your betta does not heal within 2 weeks of making these adjustments, you will need to take further steps to cure them. To cure your betta, you will even have to use a medical tank.

In and of itself, handling a sick betta in a group tank could be unsafe and stressful. Many drugs are harmful to live plants and can be lethal to marine animals. A hospital aquarium can be your solution at that moment. It is typically a simple 2 to a 5-gallon system without any decorations and only a sponge filter and radiator. Using such a hospital aquarium allows changing the water for the sick betta on a regular basis.

Treatments For Moderate Stage Fin Rot

Simply applying aquatic salts to your aquarium is among the safest remedies for still-progressing fin rot. When used incorrectly, aquarium salts will burn your betta and are toxic to most plants. You must use aquarium salts on the betta for Ten days on end. The ten days procedure includes-

  • Mix the solution with the right concentration for betta fish according to the instructions on the bottle, add a water cleanser to eliminate any chlorine from the tank.
  • Switch your aquarium or hospital tank to a location where the temperature will always be lower than 78°F. Warmer temperatures will accelerate the spread of the disease.
  • Attach a radiator and sponge filter to the hospital container after filling it with the salt solution.
  • Adjust the radiator to hold 78°F. Don’t add the betta before the solution reaches a steady temperature.
  • Treat your betta as you would to a new fish that’s about to be in a new aquarium, acclimate it slowly in the hospital aquarium
  • You have to change half of the water every day and add the same quantity of salt-water mixture to it. What you need to ensure is-
    • You need to balance the saltwater ratio while adding salt to your aquarium. If you use 3 teaspoon salt in 5-gallon water, be sure to maintain the ratio when you half the water quantity.
    • The mixture needs to be just the same as the temperature of the aquarium.
    • It’s better to make a saltwater mixture for one single-use rather than making more and storing it. Because water has the chance to evaporate and consequently the concentration of salt will be higher in the solution. It can be harmful to the betta.
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Treatments For Severe Stage Fin Rot

If the betta does not recover after treating with the aquarium salts, you will have to proceed towards the next phase of treatment. While trying to treat your fish for extreme fin or tail rot, it’s safest to use a hospital tank. The period can differ depending on the dose you used. To heal your betta, you may need to administer multiple rounds of medication. In the meantime what you need to to do is-

  • To minimize the development of bacteria, keep your tank at 78°F.
  • Change water as per the instructions of the packaging and make sure to add the required dose of dosage after each water change to maintain a steady dose of medicine
  • While using medications in the aquarium, a sponge or 1-stage filter is needed, but make sure that the filtering has no media or the medicines will be separated from the solution.


There are some proven medications available for Betta Fin Rot. If used as per directions, your fish will get rid of this disease within a short period of time. The good news is, the medicines are not that costly and can be found easily online or at any pet store.

The medication is also dependent on the prognosis of the disease.

Medications For Mild Fin Rot

The first thing you need to try is Aquarium salt. In this case, you can go for Aquarium salt by API. Follow these procedures to treat your Betta Fish with salt.

  1. Decrease the temperature to 74 degrees Fahrenheit. This decrease in temperature will make things hard for the parasites. Do not lower the temperature to an unhealthy level.
  2. Do not put salt directly into the water. Take some water from the tank, dissolve 1 tsp of salt per gallon, and gently pour it into the aquarium.
  3. You can also bring your fish out of the tank and put it inside after mixing salt, it’s a safer option.
  4. You have to change the water daily during salt treatment. Change almost 90% of the water every day.
  5. Salt treatment should not be continued for more than 10 days. If you keep your Betta in a salty environment for a long period, it will lead to fluid imbalance, electrolyte imbalance, and Chronic Kidney diseases.

If salt medication does not work properly, go for Maracyn. It is not a very strong medicine but can be used to treat Mild Fin Rot.

Make a mixture of Maracyn and Maracyn Two from Mardel. Follow the procedures below:

  1. After mixing the appropriate amount, put them into the water tank.
  2. Perform 90% water change every day.
  3. Repeat this after a 3 days interval.
  4. Continue this medication for up to 10 days, if it doesn’t show any sign of betterment, stop it, give a break for 3-4 days, and start it all over again.

Medications For Severe Betta Fin Rot / Body rot

If your Betta fish develops severe fin rot, opt for powerful medications. You can use these drugs to treat body rot:

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  1. You have to use Ampicillin and Tetramycin at the same time. If the disease is at an advanced level, consider increasing the dosage.
  2. Use one capsule each for 10 gallons of water.
  3. Open the capsule cautiously and measure the amount you need.
  4. Carefully read all the indications written over the bottle.
  5. Put the powders into the water and whip. The color will turn into Red or dark golden.
  6. Continue this medication until your fish is healed completely.

The Signs Of Healing

After you start medicating your Betta fish, you have to keep your vigilant eyes on it. Over treating can prove to be lethal as these medicines are so powerful. And your fish will become resistant to certain medications if you stop its midpoint. There’s also a high risk of getting affected by Fin rot again.

These are the signs your Fish is healing:

  • The white dots on the edges of the fins will disappear.
  • If they have completely lost their fins, you may notice some newly growing fins.
  • The fins and tails will start to look healthier. They will look better and less tattered.
  • The fins will start to turn into their original colors.

Can Fins Grow Again?

YES. After being completely or partially ragged, Betta fins can grow back. But in case of severe injury, the fin growing cells or follicles can get damaged. But it may not survive in this case.

If you notice any sign of fins growing back, take extra care of your fish. Remove any sharp substance out of the tank. Fins may grow out in different colors.

Is Fin Rot Contagious?

Gram-negative bacteria cause this disease. This is a complicated question that has both “yes” and “no” as answers. Since the bacteria and/or fungi that cause fin rot are normally present in your aquarium, every animal in the tank is at risk of infection. However, even though bacteria are present in the water, many bettas do not become ill. If your Betta develops fin rot, remove him from any tank mates he might have.

Is It Lethal?

Yes, it can be lethal as many bettas with extreme fin rot die as a result of the disease. If you wait until your fish experiences body rot before treating them, they will unlikely come back. The drugs used to treat the betta are harmful and distress the betta. A betta with a serious infection might not even be able to tolerate the procedure.

Preventing Betta Fin Rot

While it’s impossible to avoid fungi in a fish tank, it’s not impossible to stop them from attacking your bettas. what you need to do is

  • Keep your bettas in a large tank which can carry more than 5 gallons of water
  • Make sure to not clutter them with props or tank friends.
  • Maintain the optimal temperature range (75°F to 86°F) with a radiator.
  • Maintain a consistent schedule for filter cleaning and water adjustments.
  • Feed your betta in moderation.


Fin infection is not an uncommon issue in betta fish. If you identify the infection in the early stages, it’s rarely fatal. The main source of infection is low or erratic aquarium temperatures and rare transfer. The sooner you rectify the issues and cure the fish, the more likely it is that your betta will make a full recovery.

If no change is seen or betta continues to decline, you should take the route of moderate/severe fin disease treatment. The severity of the infection determines complete recovery, and whether the affected fins will develop as their previous form or not.

Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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