Betta Fin Rot

Those who are new to owning betta fish or fish-keeping in general often make the mistake of treating fin rot as a fungal infection.


This makes sense due to the brown filmy appearance you often see associated with this disease. However, fin rot is actually a type of bacterial infection (pseudomonas). Along with fin rot is body rot (aeromonas) which is more invasive and primarily internal. To check out more information on Body Rot, click here: Betta Body Rot.

Though fin rot can lead to body rot, these two infections do not always occur together. This is because fin rot is usually a primary infection. This means that infection can take place without a preceding illness. Body rot, on the other hand, is almost always a secondary infection. A secondary infection means that the illness occurs in  betta fish that are already sick with some other disease whether caused by parasites, fungus, or bacteria.

Luckily both fin rot and body rot are gram-negative, rod-shaped, bacteria meaning they can be treated with the same medications. This helps if you are unsure of which bacteria is infecting your betta fish and whether or not you are dealing with both types at once. Before we go over the causes and symptoms of this illness, make sure your betta fish is indeed sick and not just coping with an injury. It wouldn’t hurt to look over our generalized guide on betta fins before continuing. That guide can be found here: Betta Fin Problems


Fin Rot – Pseudomonas


betta fin rot

(click to enlarge)

Fin rot is caused by a bacteria called Pseudomonas which is a negative-gram, rod-shaped bacteria. Fin rot is a primary condition caused by poor water conditions usually due to a lack of water changes. When maintenance on a betta aquarium or bowl is ignored the excess food and fish waste builds up making the environment life-threatening. The excess waste in the water turns to ammonia which then breaks down your betta’s natural mucus layer. This causes stress and lowered immunities. Bacteria then starts to feed on exposed and dying tissue. The tail and fins of a betta fish are very thin which makes them the most exposed body part and gives Pseudomonas a great opportunity to infect your fish.


So how will you know if your betta has fin rot?


betta finrot

(click to enlarge)

In the earliest stages you’ll notice small pin holes in your betta’s fins and tail. As time goes by his or her fins and tail will become thin or look very translucent(like you can see through them). As fin rot worsens you will notice fraying, breakage and a build up of brown or mucus covered tips. If will look as though your betta fish is covered in algae.

If fin rot gets to the later stages it can cause permanent damage. Once your betta is healed his/her fins should go back to normal but in some cases fin rot has caused the tips of betta fins and tails to look curled once healed up.


How to treat fin rot


Fin rot can lead to secondary infections such as Columnaris so it is important to start treatment right away. First you will need to perform a water change immediately. If you’re not sure how to do a water change, click one of the following links: Clean a Betta Bowl or Aquarium Water Change. Once you have a clean habitat for your fish you will need to raise the temperature of your tank or bowl to 80-84 degrees Fahrenheit. This can be done with the help of an aquarium heater. Next add 1 teaspoon of aquarium salt per gallon. Pseudomonas is not tolerant the change to a higher level of sodium. Now add 10 drops of BettaFix per gallon(bettafix is the safely diluted version of MelaFix). The BettaFix contains tea tree oil which is used to help rebuild tissue and mucus. Mucus is your betta’s natural way to fight infections.You could also add Stress Coat if you would like to aid in recouping. Stress Coat contains aloe vera which is highly recognized for its healing and soothing properties.

Note that this is my natural method. I avoid using antibiotics as much as possible. This is because fish can become immune to them just like humans can. So if you’ve diagnosed your betta fish with fin rot in the early stages please try natural remedies before resorting to medications. When fin rot is too far along and natural remedies can’t give your betta the strength he/she needs to heal it becomes a life-threatening situation. This is when it becomes time to use an antibiotic. If you know that your betta only has fin rot you can use maracyn 2 to treat the infection. Your other option is tetracycline which I think is the better option. Tetracycline will not only treat betta fin rot but will clear up body rot as well. Be sure to follow package dosing closely so you can avoid overdose.




It is important to remember to keep up with regular maintenance to keep your betta healthy. Quality water conditions will prevent many diseases and keep your betta’s immune system running efficiently. Water changes can be tedious when you are first starting out. Once you get into the habit of performing water changes and testing regularly it will quickly become a normal routine for you.

Here are some resources to help you out:

Clean a Betta Bowl in 5 Easy Steps

How to Clean an Aquarium in 5 Steps

Also you can keep your betta’s water at about 82 degrees and add a light amount of aquarium salt on a regular basis. I follow this and have not seen fin or body rot infect my bettas or aquarium fish since 2008. Do not think of the salt as making the water being “salty”. Think of it being soft. That is why we have water softeners in our homes and fill them regularly with salt and yet when we drink we do not taste the salt. Unless you put too much in of course.

About Angela Soup

5 Responses to “Betta Fin Rot”

Read below or add a comment...

  1. Ram187 says:

    Fishie got fin rot I think he is better now, though!

  2. Anne says:

    I have a fish with bad fin rot: Would “”Natural Sea Salt be okay”? Is Betta Fix safe for a small Betta Aquarium ? would I wait until after Salt Treatment to add Betta Fix ? Or would I do a water change before Bettafix? Thank-u”~

    • Angela Soup says:

      No Make sure you buy aquarium salt for freshwater fish. Not all salts are the same composition. In a smaller tank you will only need one half teaspoon for treatment. This can be combined with Betta Fix. Just be careful to not add too much of the Betta Fix.

  3. Anne says:

    “Would adding one flake of Epsom Salts to a Betta 1 gallon tank help the Fish with “Fin Rot” or “overall health”?

    • Angela Soup says:

      For safety, be sure to purchase Aquarium Salt and use that. It’s pretty inexpensive. I get nervous with anything that isn’t made specifically for fish use. Especially because some Epsom salts contain fragrance. I hope this helps!

Leave A Comment...

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>