Fin Rot vs. Fin Tera in Betta Fish – Care Guide

Because Betta fish have long fins, they often become the victims of bullying. Their fins also snag easily on sharp edges, and they’re exceptionally sensitive to incorrect water parameters. All these things and more can lead to fin tears and fin rot. In this article, we’ll take a closer look at these two problems, specifically:

  • Differences between fin tear and fin rot
  • Identifying betta fin rot and fin tear
  • Underlying causes for these diseases
  • How to treat problems with betta fins
  • Whether or not Betta fins can heal themselves 

Let’s get into it.

Is It Fin Rot Or A Tear?

When you’re dealing with any sort of fin damage, it can be daunting to establish what kind of damage has occurred. 

Fin tears are usually really easy to spot. They look similar to a tear in a sheet of paper, or roll of cloth. There will be a split in the fin, often with a part of it leaning away from its usual place in the fin.

As a general rule, fin rot doesn’t take the form of a tear. However, since fin rot is caused by negative bacteria, it can take over an existing tear or other damage. 

Fin rot usually eats the fins from the edges inward. It may look slightly “blurry,” since the fin isn’t torn or battered, the bacteria just eat away the pieces. This means the fin may look rounded, with fuzzy edges, or it may look entirely battered and frayed.

Fin rot – Courtesy of Blair Sidorow

If you’re looking for a rule of thumb, tears often have well-defined edges while fin rot can have an extremely random shape, usually shows discoloration, and may look fuzzy around the edges.

More About Negative Bacteria 

The negative microbes that cause fin rot don’t belong to any specific species, genus, or group, so they don’t have a name. It’s a vast group of bacteria, some of which may be flesh-eating while others merely cause infections. 

At all times, no matter how careful you are, an aquarium contains some negative microbes. However, under certain conditions, (like a spike in ammonia or a dirty aquarium) they multiply rapidly to unhealthy levels. This is when things like fin rot and infections run rampant.

It’s worth noting that you can accidentally increase the numbers, and types, of negative germs by introducing water from other aquariums, or not quarantining new fish properly.

How Do You Treat A Torn Betta Fish Fin and Fins Infected With Fin Rot

When you’re treating a simple torn fin, there’s very little that you need to do. The main thing is to treat any underlying cause. I.E. If another fish is bullying your betta or nipping its fins, move one of the fish to a different aquarium. If the problem is an ornament or plant with sharp edges, remove the offending item.

Once you’ve removed the problem, all you need to do is keep the water clean and the tear will heal of its own accord.

Fin rot – Courtesy of Blair Sidorow

If you’re treating fin rot, on the other hand, you’ll need to take further action. First, you’ll need to identify all of the contributing factors. Since fin rot is related to an excess of harmful bacteria, something is wrong with the water parameters. You should: 

  1. Use a test kit to check the nitrate, nitrite, and ammonia levels, and take appropriate steps to repair any problems (if there are any). The test kit’s instructions should give you advice as to which products you’ll need to fix the problem.
  2. Use test kits to check the pH, check that the temperature is in range, and monitor water hardness. Take appropriate action to bring any problem metrics back in range. Once again, your test kit will come with instructions about how to adjust the parameter in question. 
  3. Perform a 25% water change, followed by another 25% water change the next day. This will help bring down the levels of harmful bacteria in the water.
  4. While performing the water changes, use a gravel vacuum to clean the aquarium substrate, removing any waste that might encourage the growth and reproduction of harmful bacteria.
  5. Clean the filter, washing most of the filter media but not all. Keeping some of the established filter media will help to jumpstart the positive bacteria. Cleaning the rest of the filter will ensure that there isn’t a waste buildup that allows negative bacteria to thrive.

If the fin rot is bad, you can buy a bottle of beneficial bacteria, and add that to the water. It will help replace the bad bacteria, and prevent further problems.

If you perform all these steps, your betta’s fins should start healing in a couple of days.

Potential Chemical Treatments 

Some aquarists feel that, if you encounter fin rot, you should use chemical treatments. Except in the most severe cases (and fin rot is rarely severe enough to warrant it), I’m not one of them. However, let’s take a look at two of the most common treatments:

Aquarium Salts For Treating Fin Rot 

Some keepers like to use aquarium salts to treat fin rot. It can be effective, but generally only in mild cases. Unfortunately, despite claims to the contrary, it can be stressful for your fish.

By Talita Oliveira CC BY-SA 4.0

If you’re keeping your betta correctly, they’ll be in entirely fresh water with a soft water hardness level. Adding salt to the water immediately hardens the water, and also makes the water more brackish than your fish is used to.

While the salt may kill the bacteria, it will also place additional stress on your fish, potentially opening the door for other, more severe diseases.

Antibiotics For Treating Fin Rot

Other keepers like to use antibiotics when treating fin rot. Again, this can be more trouble than it’s worth. 

Think of it in terms of blanket insecticides. When you’re growing a garden, you want to kill the bugs that eat it, right? What you don’t want to do is kill the bees, butterflies, and other pollinators that help your plants make seeds. A blanket insecticide kills all the insects, both good and bad.

Antibiotics do the same thing. While they’ll kill the bacteria that are harming your fish, they’ll also kill off the bacteria that aren’t. This means that you’re basically resetting your aquarium to the same condition as an uncycled tank, leading to spikes in nitrates, nitrites, and ammonia. 

Additionally, many aquarium medications contain sulfur or copper which are mildly toxic to your fish in their own right. 

The best way to help a fish with fin rot is to rectify the problems, and then add beneficial bacteria so that they may outnumber the negative bacteria. 

A product like Aqueon Beneficial Bacteria and Enzymes, or Tetra SafeStart Plus, used to jumpstart aquarium cycles can add the beneficial bacteria you need. If you have other, better tanks with healthy bettas, you can also use some of the substrate and filter media from those aquariums to help add healthy microbes to the tank that you’re struggling with. 

Why Are My Betta Fish Fins Tearing?

Betta fish have relatively sensitive fins, which can rip or tear for a myriad of reasons. If you notice that your betta is missing parts of its fin, that its fins suddenly look ragged, or that its fins are growing fish fungus, look for the following underlying causes:

  • Bullying – If other fish, like barbs, are bullying your betta, they may nip at its fins. The damage that results from fin-nipping can lead to secondary infections, including fin rot.
  • Plants or ornaments with sharp edges – If any of the plants or ornaments in the tank have sharp or uneven edges, the betta may be snagging its fins on those edges.
  • Insufficiently clean water – If the water in your tank isn’t undergoing sufficient filtration, the water may contain high numbers of harmful bacteria. Any reasons why your water isn’t truly clean, including inadequate water changes, can lead to bacteria buildup.
  • High nitrate and ammonia levels – Sometimes, your tank cycle might produce too much ammonia or nitrates. These chemicals can eat away at your betta’s fin, opening the door for fin rot. Generally, it happens:
    • If you don’t perform water changes regularly
    • If the filtration is inadequate
    • If your tank lacks beneficial bacteria
    • If there’s some form of waste that the existing bacteria can’t handle

There may be a myriad of other causes as well, but generally, fin rips and tears are the results of external factors like those listed above. 

How Do You Treat A Ripped Betta Fish Fin?

Generally, as long as you solve any underlying causes of ripped fins, and ensure that the water conditions are clean, you won’t need to take any additional action. 

If you’d like to give your betta a helping hand, you can use a water conditioner containing beneficial bacteria to help add further positive microorganisms to the water.

Do Ripped Fish Fins Grow Back and Repair Themselves?

As long as the damage isn’t too severe, and the water quality is high, ripped fins will grow back quite well. Even if most of the fin has been ripped off, and the fish is mobile enough to get to its food, there’s a chance that it may still recover.

To some degree, betta fins can always repair themselves. But, depending on the severity of the damage, the new fin may not look the same as the original. 

Think of it as scar tissue. While some wounds are minor and heal with little effort and no sign of the injury, other wounds are severe. While the body can heal these wounds, it also leaves behind unsightly scar tissue.

How Long Does It Take For Bettas To Regrow Fins?

Bettas with damaged fins usually repair the damage relatively quickly. If the damage is relatively minor, like a small tear or a small piece nipped off by a tankmate, the betta should heal within a week or two.

If the problem is larger, with larger pieces missing, or the damage being more severe, then it may take a couple of months. In average cases, betta fins take between two weeks and two months to recover from any damage.

Do Betta Fish Feel Pain and Do Ripped Fins Hurt Them?

Yes, like most living creatures, betta fish have nerves through most parts of their body. This means that they can feel pain just as you or I would.

Bettas also have nerve endings in their fins and damaged fins can be painful. It’s also stressful, which depresses the betta’s immune system and leaves it vulnerable to other diseases.

What Do Unhealthy Betta Fins Look Like?

Unhealthy betta fins can take many different forms. The best way to know what an unhealthy fin looks like is to know what healthy fins look like.

If you have a betta with soft, rounded fins, like the one shown above, it’s usually quite easy to see any damage. The fins will start to look torn, and ragged, and parts may be missing entirely. The point is, you can readily tell if the fins aren’t as smooth and whole as usual.

Fin rot – Courtesy of Blair Sidorow

On the other hand, if you have a betta type with lots of ragged ends, it can be quite difficult to tell whether or not the fins are getting damaged.

If you know your fish well, the signs of damage will be readily apparent, and include:

  • Discoloration
  • Tears, rips, or missing pieces
  • Missing pieces
  • In the cases of bettas with ragged fins, the edges may become shorter and more rounded

Can Fish Live With Broken Fins?

Fish can live with broken fins, depending on the severity of the break. If the break is too severe, bone marrow may leak into the fish’s bloodstream, slowly poisoning the fish.

In other cases, the break may be severe enough to prevent the fish from moving as it should. Fish that can’t move easily don’t have easy access to food, and can’t escape from predators easily. These circumstances can easily lead to the death of the fish.

If the bone is merely cracked, or the break is relatively minor, then the fish can easily restore the damage. However, with pet fish like bettas, you want to avoid offering them the opportunity to break fins.

Final Thoughts

Bettas can easily suffer damage to their fins, opening the door to secondary infections like fin rot and fish fungus. But, it’s by no means a death sentence. As long as you treat the underlying causes, your betta can make a full recovery and regrow its fins.

However, any sort of injury can lead to stress and open the door to other diseases. If your fish isn’t acting normally after it had some fin damage, we recommend having a look at our betta disease guide to help you get to the bottom of it. 

We wish you, and your betta, all the best on this journey of recovery!

About the author

Hi, I’m Johanan! I love animals of all shapes and sizes, but especially fish. I’ve gone from working at a pet store as a teenager to keeping and breeding Bettas and other fish at home. My passion for fish is endless!

You can find my articles here.

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