How To Treat Fin Rot in Betta Fish? [Complete Guide]

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Before we go into a detailed explanation of how to treat fin rot in bettas, we need to understand the bacterial phenomenon we are dealing with. Speaking of dealing with, fin rot affects all aquarium fish, but bettas are some of the few vulnerable ones.

Also known as Tail Rot, and Fin Melt, the fin rot disease is a common bacterial disease known to affect aquarium fish. Unlike the swim bladder disease, the signs of fin rot can be easily spotted.

Positively speaking, it is not as fatal as one might think, thanks to the clear signs the affected fish would likely show. Later on, we will talk about causal agents, the preventions and facts about one of the ‘prominent’ (not in a good way) disease in bettas.


What is Fin Rot in Betta Fish?

It is scientifically known as Pseudomonas fluorescens, but this is if it’s caused by bacteria (it can also be caused by a fungus). It’s a fungal infection or gram-negative bacterial infection. A disease of this nature is prevalent amongst fish super bowls and uncycled tanks.

It starts by attacking the tail or fins of the betta fish, destroying its precious fins. Also, you can come across this when you buy bettas from big thanks, and this is no thanks to the poor quality of the water and the overall temperature of the tank where the betta inhabits. So, it’s safe to say that this could affect any betta irrespective of the size of the tank where they are kept.

However, the fin rot disease should not be confused with fin splitting, biting, or tearing. The result of the four looks alike, but are quite different when we take a closer look. While fin rot is a disease, the other three are mainly physical injuries.

Asides fin rot (obviously), the rest is as a result of aggressive tank mate or vice versa. Also, these physical injuries can also be a result of boredom or been ripped up by the aquatic decorations.

Having full knowledge of these things will be helpful later on simply because you don’t want to be medicating a healthy betta fish. What to look out for? Black, white, or red edges around the betta’s fins.

Fin Rot Disease in Bettas – The Causal Agents:

Before we highlight the causal agents, you need to understand the fact that fin rot in bettas is not as fatal as you might think. Knowing the causal agents will help you filter out the right medical procedures to follow when treating fin rot in the betta fish, after all, prevention is way much better than cure, right? So, what are the causes of Fin Rot Disease? Some of the causal agents include:

  • Poor Water Quality.
  • Unfavorable water temperature.

The major causal agent is poor water quality. We all know how sensitive bettas are to the quality of water, and how the sudden change in its quality can affect his health. Poorly treated water is the perfect haven for fungal, parasites, and fungal.

Not taking good care of the water leads to all sorts of infections, all of which aren’t good for your betta fish. Ultimately, polluted water enhances the growth of the unhealthy organism in the tank. Also, it will weaken your betta’s immune system. We both know what comes next when the immune system becomes depleted and weakened, it makes the betta susceptible to different infections, one being the fin rot.

How to Take Care of The Water Condition:

When it comes to taking care of the water conditions, there are certain things that need to be in place and taking note of. Some of which are

  • Keeping the temperature of the tank below 78 degrees Fahrenheit.
  • Making sure the water is not cloudy or milky. Both are signs that the water is polluted. Do not allow the quality of the water to deteriorate to this point, but if for one reason or the other, it does get to this point, make sure the water is drained out and replaced with a new and clean one.
  • The usual cause of milky or cloudy water is due to the pieces of feed remnant, fish feces that are in the tank. Siphon the dirt out and run adequate flow through or change the water completely.
  • Also, check to see if the nitrate, nitrite, and ammonia level is high. The ammonia and nitrate level should be at 0 parts per million (ppm), while the nitrate level should be at 20 parts per million.
  • Make sure the tank is also cleaned ones in a while. After siphoning the dirt out and reducing the water level, get a clean and dry cloth or foam and get the tank cleaned.
  • Lastly, ensure that the betta is getting all of the comforts that it deserves. You don’t want a stressed-out betta, as this also contributes to the growth of the infections.

Asides poor water quality, what else could cause this infection? Apart from inhabiting a tank with poor water quality, fin rot can also occur due to underfeeding as well as overfeeding.

An irregular feeding pattern ca stress your betta. When you underfeed and overfeed your betta, it weakens their immune system and increases their chances of been infected with the fin rot disease.

The Two Forms of Fin Rot in Bettas (and other aquarium fish).

It’s no longer breaking news that the fact that fin rot is in two major forms. It can be bacterial or fungal. In fact, when it comes to treating fin rot in betta, one of the things you need to know is whether the fin rot disease is fungal based or bacterial based. This will define the kind of medication the betta will receive.

              · Fungal Fin rot

One of the two forms of fin rot is the fungal fin rot. If a betta is suffering from the fungal fin rot disease, the rot will appear more across the betta’s fins. You may also notice whitish spots on the betta’s fins. But this should not be confused with ich. This is another infection that is known to cause a white spot on the betta’s fins.

               · Bacterial Fin Rot

Next is the bacterial fin rot. Unlike the fungal fin rot which is known to cause white spots to appear on your betta’s fins, the bacterial fin rot, on the other hand, causes uneven spots on the fins. It infects your betta when his immune system is weak. It ‘attacks’ your betta once the immune system is weakened and can’t fight it. To avoid this, ensure the cleanliness of the water where the betta is kept.

Fin Rot behavioral signs in bettas and other aquarium fish

When the betta’s fin and the tail are disintegrating or already damaged, he knows this. He can also feel this too. It causes listless. Also, to help ease the pain, you may find your betta rubbing itself against the water decorations you have in the tank or the tank wall. Asides these, there are no other recorded behavioral changes in bettas when they have this disease.

Can Fin rot in bettas be caused by stress?

At this point, we all know how stress can be a major player when it comes to betta infections such as the fin rot. When stressed up, irregular feeding patterns, coupled with poorly treated water, you are bound to get something sinister in the tank.

Symptoms of Fin Rot in Bettas:

How do you know if your betta is suffering from fin rot? Just as we’ve stated earlier, the signs and symptoms of fin rot are physical and can be seen with the naked eyes. But first, run a proper diagnosis to find out what the real problem is before offering your betta any form of medication. The symptoms are determined by how long the betta has stayed infected.  It comes in three stages.

First stage.

The first stage is always more glaring as the fins and or tail will start to discolor, especially on the edges of their fins and tails. Usually, the discoloration appears as red, black, or white.

Second Stage.

At this stage, the edges of the fins will start to look uneven and stained. It gets to a point when the infected parts start to peel off.

Final Stage.

It gets so bad that the entire fin and tail become rotten. It peels off and starts to affect the body. Even though we stated earlier that fin rot is not as fatal as one might think, it doesn’t mean that this is not possible. When the infection starts to attack the body, if not treated fast, it could lead to the betta’s death.

Signs of mild fin rot in Bettas:

What are the symptoms of mild fin rot in bettas? Mild in this context means the disease is at its early stage. At this stage, there is always a high chance of survival. The earlier you able to spot the infection, the better for the fish. What are the common signs of mild rot in bettas? They are:

  • The betta’s Fins turn slightly darker.
  • The tips of the fins and tails will start changing to white, grey, or dark red.
  • Also, the fins edges may start to appear rough, tattered, and completely worn out.
  • You’ll start to see red spots or sores on the fins of the infected betta. Asides sores and red spots, you may also see irritations on the betta too.
  • Finally, just because it’s still in the mild stage, you won’t find any of these spots on the betta’s body.

Signs of major fin rot in Bettas:

  • Unlike the mild stage, once the fin rot gets to this stage, the chances of your betta surviving it decline gradually. Which is why we always insist that you spend quality time with your betta. You’ll start to notice:
  • The fins and tails totally chopped off. Once this happens, the infection jumps on the body of the betta and continue this vicious act.
  • You may also notice some chunk of the infected part of the fins falling off in the tank at once, instead of the usually gradual peeling off.
  • More than half of the fin become dead and rotten.
  • The discoloration process at this point becomes glaring. The fins will become dark as a result of the infected spots dying off.
  • Asides peeling away, you may also start to notice the entire fin covered in a white substance.
  • Most of the time, the infected parts have red spots.

Signs of severe fin rot in Bettas:

  • At the stage, it’s safe to say that the chances of your betta surviving this is very slim. If the rot gets to the body, then you will have to work extra hard to salvage the situation. So, what are the signs of severe fin rot in betta fish? they include:
  • The fins and or the tail have completely receded down to the body.
  • Your betta’s body has been infected too. When this happens, the body part starts to rot
  • Lastly, you may find a white substance where the fin or tail used to be.
  • At this stage, the entire fin and tail would have been chopped off. The severity means that the entire body has been infected by the disease.

How to Treat Fin Rot Disease in Betta Fish

When it comes to treating fin rot in bettas and other aquarium fish, depending on the stage of the disease, you have to be proficient, quick, and precise. the severity and progression of the fin rot can be halted if /when you do the right thing at the right time.

The key thing here is setting up a quarantine tank and isolating your fish before proceeding with the treatment. Before we proceed with the treatment details, you need to know in full details all it takes to set up a quarantine tank. When we said we wanted to share with you how to treat fin rot in bettas complete guide, we meant it.

When isolating your betta, you need to help your betta reduce the risk of infections spreading across its entire body. isolating your betta won’t only be beneficial to your it, but it will also be beneficial to the tankmates too. So, to prevent the spread, setting up a quarantine is your best bet. Here’s how you set up a quarantine tank.

How to Set up a Quarantine Tank for Fin Rot Infected Betta:

In case you have a betta with no tank mates, then you don’t need to do this. This section of the piece is to place a spotlight on how to perfectly set up a quarantine tank for bettas with tank mates. Before we proceed, you should also understand that smaller tanks are usually the best for this.

Small quarantine tanks are great because it allows you to make seamless medical decisions when treating your fish. It also allows you to change the water effectively. So, the recommended size for quarantine is 2 gallons. If you can, make sure it stays filtered and heated as well.

Step 1.

The first step to a perfect set up is adding water to the quarantine tank. The tank should be filled to the top with properly regulated water.

Step 2.

Once the first step is complete, the next thing to do is to install a filter and heater in the quarantine tank. Also, you shouldn’t forget to add the right medicines too.

Step 3.

When the temperature of the tank gets to the needed point (which is 78 degrees Fahrenheit), take your betta out from the regular tank and place it in the quarantine tank. Additionally, the quarantine tank should have decorations that will let your betta hide and play during the treatment process. But you should try as much as you can to make sure that these decorations don’t have edges and surfaces that could hurt your betta. Try adding fake silk plants.

Step 4.

Acclimatize your betta before placing it into the tank completely. The easiest way to go about it is by placing the betta in a bag filled with the water gotten from the regular tank. Let go of the bag and let it float in the tank for 10 to 15 minutes before completely releasing it into the quarantine tank.

Step 5.

At this stage, the betta is now in the tank ready to receive treatment. The next thing to do at this point is to change the water partially. At least, 25% of the water should be removed from the tank. The change should be made every 72 hours.

If for any reason, you aren’t able to filter the quarantine tank, then a complete water change should be done. However, before the complete change, you should first, place your betta in a small bag filled with the quarantine water.

The conditioned water should be added to the quarantine tank for completely acclimatizing your betta to the quarantined environment. This is important for the overall health safety of the tank.

Also, treating betta with fin rot depends on its size, and the ‘habitat’ too. Diagnose the problem, know how to channel your treatment, and lastly, use the right method. Let us share with you the right way to treat fin rot in bettas in different stages of the infection.


How to Treat Mild Fin Rot Disease in Bettas:

  • When treating mild fin rot in bettas, the first thing you need to look for is the tank’s temperature and PH level. While the temperature of the tank should be close to 78-degree Fahrenheit, the PH level on the other needs to be in the range of 6.5 – 7.5. Also, you should make sure 50% of the water in the tank is removed and replaced with conditioned/non-chlorinated water.
  • While extracting the water, siphon the excess food and feces in the tank by using a gravel vacuum to suck it out. If you have a filter in the tank, clean it (filter) in the tank to ensure that the good bacteria stay in the tank. If you any old decorations in the tank, you either wash clean or replace it totally. When washing the decorations, make use of hot water and avoid using soaps. If you have more than two fishes in the tank, you should consider taking some of them out.
  • What you need to keep doing at this stage is to keep a closer look at them, to monitor their health change trajectory. Are they showing signs of improved health-wise, or is their health degenerating? You need to be patient as this can be a relatively slow process. What you will start noticing when their health starts to improve is the disappearance of the white substance on their tails and fins. The brownish spots stats to fade out, and ultimately, you will see the ‘birth’ of a new fin. Don’t forget to continue changing 25% of the water in the tank.


How to Treat Major Fin Rot Disease in Bettas:

Just as we stated earlier, as this stage, your bettas chances of surviving are relatively high. These are the things you need to do when treating major fin rot disease in bettas.

  • Understand that you’ve got to be aggressive at this point. If you have plants or tank mates, you will need to isolate the betta, a form of quarantine. Simply place, you need to place your betta in a hospital or quarantine tank for proper monitoring and efficient treatment. The hospital or quarantine tank has to be filled with well-regulated freshwater; the water has to be heated. The proper size of a hospital or quarantine tank should be about 1 – 2 gallons. The betta needs to be acclimated properly when in that quarantine stage.
  • To make that the bacteria stay in the tank, you need to clean the filter in it, do not bring it out. After cleaning the filter in the existing water in the betta’s tank. If it has not tank mates, you should do a complete overhaul. Meaning, changing the entire water, and washing all tank decorations in hot water. So, what are those things that need to be cleaned? From the tank, gravel, the décor, live plants, down to the heater. Replace the replaceable and fill the tank with properly conditioned water.
  • Next, treat your betta with aquarium salt. However, the salt treatment should only be applied in the quarantine tank. This salt helps your betta heal faster, it also inhibits the nitrate uptake and wicks out stress. Combine properly conditioned water with 1 to 2 teaspoons of aquarium salt in a different container. This will help dissolve the water effectively before pouring it into the quarantine tank. You need to take note of this; not properly dissolving the salt could be counterproductive as this could lead to burns instead of healing.
  • Lastly, pour in the dissolved salt coupled with the properly conditioned water mixture into the bettas quarantine tank. You should also apply the right proportion of water to the quarantine every day before applying a new dose of salt to avoid an increase in the salt concentration in the tank. This could kill your betta. 50% of water change is ideal. The dosage should be repeated for up to 7 days. Also, while monitoring the signs of improvement health-wise.


How to Treat Severe Fin Rot disease in Bettas:

At this stage, the goal is to reverse its damaging effect. There are medicines that are designed to help with this. When you start to see the fuzzy growth, then this is obviously severe. As usual, isolate your betta in a new tank and acclimatize it to the quarantine tank properly with regulated and heated water.

You should also add a bubbler or airstone as a form of medication. Bubblers and airstone can help bring back the oxygen lost in the water during the application of different medications. In case you are treating the betta in its regular tank, you should wick out carbon from the filter to ensure that the medicine stays in the tank.

  • Drain the water in the main tank out, including all of the components (the decorations and tools) in the tank and clean all of them properly using hot water. couple everything back and fill the tank with freshwater. The water temperature needs to be 78 degrees Fahrenheit. In case you have a filter, you need to start running it to ensure the nitrogen cycle is activated while the betta is still in the hospital or quarantine tank.
  • The antibiotic you administer should be recommended. Meanwhile, administer the antibiotic properly into the quarantine tank. The dosage should not be halted before the due date as this could cause antibiotic-resistant bacteria in your betta. Change the water proportionately before adding the new dosage. If a new antibiotic is added without first taking out the previous water, that could cause an overdose.
  • Now, place your betta in its previous tank and let it acclimatize to the tank once the treatment is complete. However, the water management routine should not be stopped. Ensure that the water is cleaned on a daily basis. Also, water should be kept warm. Finally, avoid overcrowding the tank. It’s not wrong for you to add a tank mate, but the thin line is trying to add too much.

you are done with the treatment, you’ll start to notice the growth of new fin membrane, hopefully, that should be the beginning of a new comfortable life for the fish. The old, rough and jagged spots would have faded away. It’s important to note that fin rot has a creepy pedigree of coming back after treatment. Like we said earlier, be consistent with your treatment. Getting to this severe state is mostly because of your negligence. Hopefully, this time, you won’t let that happen.

Betta should be taken care of on a regular basis to help prevent fin rot infection from attacking your fish again. You shouldn’t expect your betta’s fins to grow back to how they were. The old and the new fins don’t always look the same. The new fins and tails tend to look shorter, or longer and slightly disfigured, or cleaner when compared to the old one.


How to Treat Fin Rot Using Aquarium Salt:

We lightly stated the importance of aquarium salt when treating fin rot in bettas. But the importance should not be underrated. Without a doubt, aquarium salt is very effective when treating fin rot disease in bettas and other aquarium fish. While some medications are known to be harmful to your betta’s labyrinth organ (the labyrinth organ is used by the betta to breathe), ono the other hand, aquarium salt may stress out your betta, but it won’t in any way affect your betta. However, you should ensure that the salt is applied properly.

When using the aquarium salt, there are some things you need to take note of, as this could be a matter of life and death for your water pet.

  • The correct dosage should be used when been applied to the betta’s tank. The instruction is usually on the product. Take note of the instructions.
  • Also, betta owners should not use this salt beyond 10 days periodically. Anything other than this could hurt your betta’s liver and kidney. Bettas are not supposed to be exposed to salt for a long time.


We all recognize the fact that there are lots of illnesses that can affect your precious water pet. That is why it is important to properly diagnose the infection or illnesses before proceeding with the treatment. From ich, Velvet, dropsy, cloudy eyes, reasons why your betta is swimming erratically, down to fin rot disease.

While we will be sharing the complete guide to these other infections and illnesses. This piece on how to treat fin rot in bettas has all you need to make sure your pet is kept safe from the jaws of this skin eating infection. Let us know your thoughts in the comment section below.

1 thought on “How To Treat Fin Rot in Betta Fish? [Complete Guide]”

  1. Hello Shahid,
    Thank you for the comprehensive information! I’ve been wondering what’s going on with my Black Orchid Betta. His fins have always been mostly black, with a hint of blue near his body. I first noticed a small red spot on his ventral fin a couple weeks ago. Then more recently I noticed some little holes in the centers of his tail fin and dorsal fin (not at the edges). The holes have gradually expanded into huge tears. I now also see a small red spot on the front of his dorsal fin. His pectoral fins and anal fin and body still look fine. I have researched this stuff for hours and can’t seem to find out what this is or what to do. Any ideas for me? I am happy to send a photo if you’d like. Thank you!


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