How To Treat Betta Fish Fin Rot? Step By Step Guide


One of the most striking features about Betta fish are their fins.  Colorful and fascinating, they are what give these graceful creatures their character and yes, value.  But, on the other hand, these fins are also very sensitive areas to Bettas and that’s why they’re the first part to get sick. So, when fin rot happens to Betta fish, it’s very noticeable.

Fin rot is the most common problem of Betta fish owners.  It can be described as fins cut up, torn, or melting away.  The edges often look black, receding, and severely jagged.

Most fin rot occur at the caudal or tail fin.   It starts with discoloration.  Sometimes the rot may appear white, but more often than not it will be black.  That black part is actually dead tissue.  There are extreme cases when the tail is bleeding or just looks missing.

Why Does Betta Fish Fin Rot Happen?

Aquariums contain both good and bad bacteria.  Normally, Betta fish aren’t affected by the microbes unless its immune system is compromised.

When aquariums are not properly maintained, the amount of microbes becomes overwhelming.  Too much gram-negative bacteria or pathogenic fungi in the fish’s environment cause Betta fish fin rot to occur.

Substances that naturally occur in the water primarily from fish excrement and residue are ammonia, nitrites, and nitrates.  These are also very harmful to fish, thus the need for periodic water change and tank cleaning. 

It’s the same for Betta fish.  These beauties deserve more than staying in a bowl, so don’t even consider that.  And maintaining aquariums for Betta fish shouldn’t be that hard.  With regular water changing and tank cleaning, your Betta fish should stay happy and healthy. 

Keeping the waste down sometimes is just a matter of toning down the amount of food.  Overfeeding fish causes more waste to float around its environment, polluting the water.  But hey, don’t make the food scarce either.

Sometimes, there are people who bring home Betta fish from the pet store that may already be infected because they might’ve been sitting in the same tank for a long time.  Good thing you took Spike, that exquisite Betta home, though, so he can receive the proper care he needs to thrive.

Speaking of germs, there are different types of pathogens causing fin rot disease.  These include pseudomonas fluorescens and vibrio parahemolyticus which can also cause infections in humans with low immunity.  The latter is even popular for causing intestinal flu in humans.  But there are also pathogens particular only to fish. 

Can Betta Fish Heal On Its Own From Fin Rot?

Fin rot becomes progressively worse if not treated.  This disease threatens your fish’s immune system, and so they may eventually die if nothing is done. 

But don’t worry, Betta fish fin rot treatment doesn’t mean antibiotics right away.  Assess the situation for severity before you run to the pet store and rack up the bills in panic.  Besides, your buddy Spike may benefit more from natural methods.

What Are The Treatments For Betta Fish Fin rot?

Oh no, Spike is sick!

Once you’ve verified that your pet does indeed have fin rot, separate him right away from other fish in the tank to prevent him from infecting others.  Set up an isolation or hospital tank for your infected fish where you can add in treatments to the water to help him heal.

How To Treat Betta Fish Fin Rot? Step By Step Guide
How To Treat Betta Fish Fin Rot? Step By Step Guide

And then try these:

1. Grab A Box of Aquarium Salt

Mild Betta fish fin rot can be treated with the right amount of aquarium salt in the water.  Aquarium salt or dried sea salt has more nutrients and is more natural than the table salt we find at the grocery store.  It is a natural antifungal and antibiotic.

A higher concentration of aquarium salt than what is indicated in the box should be used when treating Betta fish fin rot.  This is about 1 tablespoon for every 3 gallons of water.

Do not add the salt directly to the aquarium.  Pure salt can burn and you don’t want to worsen an already hurting Spike.  So the key is to pre-dissolve the right amount of salt completely in water before adding it to the tank. 

2. Change The Water Every Day Until Your Fish Looks Healthy

Spike is at the hospital, and one thing about hospitals is that it’s kept sanitary.

Keep changing the water every day, adding in the right amount of aquarium salt each time. Partial changes of about 50% of the water would be enough, which means the proportion of salt in your solution should correspond accordingly. 

Remember, infected water will keep your fish from healing and might even cause secondary infection as it still contains the microbes that are still harming your little Betta.

3. Add Indian Almond leaves to the treatment

The dried leaves of the Terminalia Catappa Tree native to Southest Asia also has antifungal and antibiotic properties, and a lot of Betta fish owners swear by it.  These are available online.

A hand-sized (or 6 to 8 inch) Indian Almond leaf is enough for a tank of 10 gallons, but some people use double that.  Simply wash the leaf and tear them into small pieces.  The soaked pieces will sink in the water after about half a day.

You can also opt for tanning the water first by soaking up the leaves in boiling water.  After the temperature has become just right, you can now add the tanned water to the tank.

Dried Indian Almond leaves are natural and harmless to your Betta fish, but some owners argue that they don’t want to darken their tank too much so they can observe the fin rot better.

While they may look ugly in your tank, Indian almond leaves mimic the natural habitat of Betta fish.  They release helpful tannins that fish appreciate, and you will too, if you look at your aquarium as more natural-looking.  Some tank keepers even regularly use tannins to prevent the onset of Betta fish fin rot.

Spike may be getting treatment at his isolation facility, but he’s more relaxed as his environment feels homey.

4. Bettas Like Tropical Temperatures, Use A Water Heater

Wild Betta fish come from tropical waters.  That means anything outside of ideal temperatures can stress out little Spike.

Isolation tank water should be kept between 75 to 82 degrees Fahrenheit. Any lower than that and your fish’s immune system gets weaker.  Higher temperatures cause your fish stress.

With the right amount of warmth in the water, Spike feels just like being hugged by a nice, comfy blanket.

5. If You Use A Water Filter, Choose The Kind That DOES NOT Create Current

What Spike doesn’t appreciate especially now that he’s feeling a little off, is a lot of noise and movement.

Betta fish don’t thrive well in tanks with current, so avoid water filters that have spray bars or those that tend to vibrate, and loudly at that. 

Filters help neutralize nitrates and ammonia as well as maintain the right amount of beneficial bacteria in your tank.  But don’t go over the top.  Betta fish tanks smaller than 3 gallons often don’t need a filter at all.

So, you should be seeing changes in your fish’s fin in a matter of days.  If the Betta fish fin rot is not healing, then the problem can be more severe than you thought.

6. If The Problem Is Persistent, Use Medication

So… Spike isn’t getting better.  At least, not by much.

If your Betta fish fin is still receding even after a week of treatment, you may want to use medications available at your local pet store.  But if you want to keep it natural, here are some options.

One such treatment is ParaGuard, a methanol and formaldehyde-free medication and therefore still milder than aggressive antibiotics.  A capful (or 5ml) of ParaGuard daily is safe and does not alter your water’s pH level.

Another similar Betta fish fin rot cure for infections is a combination of Jungle Fungus Clear and Kanaplex.  The active ingredients in these medications fight fungal infections as well as both the gram-positive and gram-negative bacteria that cause fin rot.

Use a tablet of Jungle Fungus Clear for every 10 gallons of water.  Just cut up the tablet if you’re using a smaller isolation aquarium.  This dose is good for 4 days.  The Kanaplex is added using the scoop.  One level scoop is good for 5 gallons of water, and is good for 2 days. 

Obviously, with the JFC and Kanaplex combo you will have less water changes as you let the medication take its effect.  After 3 doses of Kanaplex, let the tank rest for a week.  The difference in the fin rot should be very clear by now.

7. Antibiotics For Severe Betta Fish Fin Rot

Betta fish that are weaker or older tend to have lower immune systems, and when fin rot occurs, you might find yourself fighting a more particularly tough infection. 

There are antibiotics available for Betta fish fin rot like Fritz Aquatics’ maracyn or API’s erythromycin.  Both are the same medicine and geared primarily for fin rot, fungal infections, and open wounds.  Erythromycin is a broad-spectrum antibiotic, meaning it kills a whole range of bacteria.

Betta fish fin rot
Fin rot in Betta fish

Combining erythromycin with an antiseptic like Methylene Blue or Ich-X can help as they are more of a cleansing type of treatment.  It may help prevent the occurrence of secondary infections.

It is important that when treating with Betta fish fin rot medicine such as erythromycin, you should take out your filtration systems.  That includes activated carbon from the tank as this will reduce the effectiveness of the medicine.

Water changes with strong antibiotics are even less at once a week.  Just make sure to oxygenate your tank properly to help fish feel more comfortable during treatment.

8. Get Your Water Tested More Often

While treating your Betta fish fin rot with antibiotics, make sure to get your water tested more frequently than once a week. 

Test kits are available at your local pet store and are very useful in checking water quality including ammonia, nitrite, and nitrate levels, as well as pH balance. 

9. During Treatment, Be A Lot More Observant

Smile for the camera, Spike!

One way to monitor if your fish is getting better is by taking pictures of it every day.  You can easily compare changes better in photos because your fish isn’t moving. 

It’s also imperative to watch out for signs of stress.  If by chance you’re treating your Betta fish wrongly, you’ll see signs of lethargy or lack of enthusiasm for food.  When this happens, do a water change and use activated carbon to soak up any residual medicine in the water. 

After letting your tank rest for several days, you can start over with another kind of fin rot treatment, probably less or more aggressive depending on your assessment.

Will the Betta Fish Fins Grow Back After The Fin Rot Treatment?

Now that the disease isn’t progressing and your fish is behaving and eating normally again, most people ask if the Betta’s fins will regrow.

Betta fin rot
Fin rot in Betta fish

Since Betta fish fin rot is pretty common, most fish will heal nicely after treatment.  You’ll notice white tissue growing back on the fins as they regenerate.  Pretty soon, these fins will look the way they once did before acquiring fin rot.

Some owners only use antiseptics after the antibiotic treatment.  Products like API’s Bettafix can be used to help Betta fish hasten the regrowth of their fins, though most find it unnecessary.

If you are interested in learning more about your fish behavior, check out the links below:

What Can You Do To Prevent Betta Fish Fin Rot Next Time?

Avoid stressing out your fish.  Keep your aquarium clean and keep your Betta fish’s immune system healthy.

It may help to have a schedule for changing your water.  Set up a reminder or a log for water changing.  We admit it, we get busy, we get forgetful.  But Spike is counting on you and he’ll really be glad if you do it regularly.

Betta fish normally don’t get fin rot just because there are pathogens in the water.  But a contributory factor to getting infections is if they’re stressed or already unhealthy to begin with.

Review all the causes of Betta fish fin rot listed above and avoid them.  With all these tips and tricks, Spike will heal and live a full 4 or 5 years swimming in his tank, keeping both you and him happy.

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