Betta Fin Rot Vs Fin Loss (How To Tell The Difference)

The beautiful flowing fins of the betta fish are one of the trademarks that make the fish such an amazing pet to own. Not only their color but the way they flow through the water as the betta fish swims is completely unique among fish, making them a popular pet for many fish lovers. 

That’s why when something appears to be wrong with the fins of your betta fish, it can definitely be alarming. Getting to the root of the problem quickly is very important for the health of your betta. So is it fin rot or fin loss? Fin rot is a bacterial infection that eats away at your betta’s fins, while fin loss refers to physical damage inflicted on the fin. 

Each has its own countermeasures and treatments, so it’s very important to quickly identify which is the problem and try to solve it as soon as possible. Read on to find out everything you need to know about betta fin rot vs. fin loss. 

What is Betta Fin Rot?

Fin rot is a condition caused by a bacterial infection that causes the fins of your betta fish to become ragged and tattered. Blackened, bloody fins and fins falling off or rotting away are pretty surefire signs that your betta could be experiencing fin rot. 

Fin rot is categorized as a gram-negative bacterial infection, which is usually the result of poor water conditions or water hygiene. Betta fish are awfully sensitive to improper water conditions. 

Betta fin rot is pretty easy to see if you check up on your fish regularly. The fins will appear ragged, and the tips or other parts of the fin could appear blackened or bloody. If your betta fish is dark in color, look closely because it can be hard to see blackened fin tips. 

What Causes Betta Fin Rot?

There are a number of things that cause betta fin rot, but the main contributing factor is that your betta is living in fluctuating or improper water conditions. As mentioned above, betta fish are very sensitive to the parameters of their tank and need to be in water that satisfies a pretty specific set of parameters. If they don’t, they will likely begin to develop fin rot. 


The main cause of betta fin rot is a bacterial infection that comes from stress. Stress occurs in bettas when they are kept in tanks that have improper conditions.

It might not seem like it, but betta fish can get very stressed out from being in an environment that doesn’t suit them, and it certainly affects them physically. This is why keeping your betta fish well-fed and in the proper environment is very important. 

Improper Water Temperature

One of the most common reasons for stress in betta fish is that their tank is filled with water of the wrong temperature. Bettas are tropical, freshwater fish.

This means that they prefer to be in fresh, warm water. The best temperature range to emulate the waters that they live in naturally is between 75 and 81 degrees Fahrenheit. This means that your tank is going to need a reliable heater. 

Improper pH

Another possible issue with the conditions of your betta’s tank is an improper water pH level. A pH level is a number that tells you how acidic or basic the water in your betta’s tank is. Betta fish like water that is fairly neutral, meaning they do best at around a pH of 7.

However, a range of 6.5 – 7.5 should be just fine and a comfortable environment for your betta to live in. 

Improper Water Hardness

Water hardness is another factor that could, if it is not properly attended to, cause fin rot in your betta. This is probably the least well-known of all the parameters of aquarium water, but it is important nonetheless. 

Basically, the “hardness” of the water refers to the amount of calcium and magnesium that has been dissolved in it. “Hard” water has a lot of magnesium and calcium, while “soft” water has less of these minerals dissolved in it. Hardness is measured in degrees of general hardness, or dGH. One dGH is 17.9 ppm or 17.9mg/L. 

Healthy hardness for the water in a betta’s tank is between 3 and 4 dGH.

Improper Ammonia and Nitrite Levels

If your aquarium’s water has too much ammonia or nitrite, this could also be a problem that leads to fin rot. In fact, the ideal level of ammonia and nitrite in your fish tank is zero. Nitrates (different from nitrites) should be at around 20 ppm.

Betta fish, Siamese fighting fish with green plants

How to Cure Betta Fin Rot

If these levels are too high, you should do a partial water change as soon as possible. If these levels are continuously an issue, your filter could probably use replacing. Make sure to measure these with ammonia and nitrite test strip kits often to ensure your betta’s environment is healthy. 

Now that you know what causes betta fin rot, the next step is figuring out how to fix it. Getting your betta fish’s fins back to normal will not only be more comfortable and healthy for the fish and allow it to swim freely, but also get it back to looking as vibrant, colorful, and healthy as it can!

If you need proper guidance on taking care of your Betta fish, click here to read a comprehensive article on betta fish care! 

Clean The Tank

Cleaning your tank is among the easiest ways to change the water parameters and environmental conditions that could be causing the stress that leads to your betta’s fin rot. 

First, you can leave your fish inside the tank when it’s cleaned. Start by wiping up some of the algae and other debris that has probably built up on the bottom and sides of your tank. You can rinse the lid off in your sink if there are algae on that too, but don’t use soap. 

Clean up any dead plant matter or foliage and other larger debris with your hands and take it out of the tank as well. If you have an aquarium vacuum, make sure you vacuum your substrate as well. Click here for a detailed guide on vacuuming your aquarium. 

Clean the filter as well. Arguably, this is the most important part, as this is what will keep your tank a healthy environment for your bettas to live in. Take it out and swish it around some fresh, clean water. Do not use soap, as it can harm your fish!

Partial Water Change

If you don’t feel the need to clean out your entire tank, a partial water change might do the trick. Old water might be the cause of the fin rot, so changing it out can be very helpful. 

Get a large container and fill it with fresh, clean water. Use a water conditioner (available at pet stores) to prepare it and remove harmful chemicals. Then, warm up the water to the proper 75-80 degrees Fahrenheit for your betta. 

Next, slowly replace the water in your aquarium with the new freshwater. Remove 25% of the water in the aquarium and then replace it with the new water. The goal isn’t to completely replace all the water, but just replace some of it with fresher, cleaner water. Doing this frequently can significantly decrease your betta’s risk of fin rot. 

Change the Water Parameters

Changing the water parameters is another major way to stop fin rot in its tracks. Make sure that your water temperature is 75-80 degrees Fahrenheit, your pH is between 6.5 and 7.5, and your water hardness is 3-4 dGH. 

If any of these are off, you’ll need to change them to fit the proper parameters as soon as possible. If the temperature is off, simply turn your water heater up or down a bit accordingly. If the pH is off, there are plenty of products you can get to make your water more acidic or basic at pet stores.

Similar solutions are also available for making your water harder or softer. 

Oftentimes, just making sure your water is within the healthy parameters for betta fish can stop fin rot and allow your betta to begin healing. 

Treat With Erythromycin

If the fin rot is severe enough, it might have to get treated with medication. There are a number of medications made to treat gram-negative bacterial infections in fish, such as erythromycin or another fish-appropriate antibiotic. Consult with a fish expert or an aquatic veterinarian before giving drugs to your fish, as you want to be certain that it’s the correct decision. 

This is really only a solution for fin rot that has progressed to a pretty severe stage. Still, it is an option that’s on the table and should certainly be considered!

Treat With Aquarium Salt

If the antibiotic you need isn’t available to you, there is an alternative solution. Aquarium salt can also be an effective antibiotic for fish, including betta fish, that are experiencing fin rot. One teaspoon per gallon of water in your tank should be enough. 

Be warned, however, that aquarium salt is only good for live-bearing fish. Some fish, such as scaleless catfish, are quite sensitive to salt. This means you need to consider your betta’s tank mates before using aquarium salt as a solution to fin rot. Make sure the salt will not harm any of them before using it as a potential cure. 

What is Betta Fin Loss?

Betta fin loss is not the result of infection but the result of any sort of physical damage inflicted upon the fins of your betta fish. Since they are so long, flowy, and delicate, betta fish fins can often be caught on edges and snag, rip, tear, and experience other kinds of damage as well. 

The only way to identify fin loss is to look at your fish regularly and make sure the fins look healthy and untorn. Fin loss can also lead to fin rot, as wounded fins cause stress and are more susceptible to infection.

What Causes Betta Fin Loss?

Fin loss refers to any kind of damage inflicted upon fish fins. However, there are some things to look out for that cause fin loss in betta fins more often than other contributing factors. Read on to find out what the most common reasons that fin loss occurs are. 

Fin Npping

One of the main reasons betta fish fins become ripped or torn is that they are being nipped by other fish’s fins. Betta’s are aggressive fish and have been known to fight and can sustain damage in those fights. Not only this, but improper tank mates can also cause betta fish to get nipped at by other aggressive fish when they aren’t the fish provoking the fight themselves. 

Plastic Plants

Plastic plants are one of the major causes of fin loss. This is because they are often sharp and can catch the long, flowing ends of betta fish fins and tear through them easily. 

Sharp Edges

Sharp edges such as the corners of decorative pieces, driftwood, and other corners and edges can tear at the delicate fins of your betta fish as well. If there are a lot of these in your tank, you may have found your culprit.

Rough Substrate

Substrate that is too rough can damage the fins of your betta fish as well. Make sure that you have a soft substrate with rounded edges, such as fine, soft gravel or pebbles. Betta fish do sometimes like to hang out near the bottom of the tank, so swimming above rough substrate will damage their fins.

Other Damage

The above are the most common reasons fins are damaged, but like any other injury, any number of things can cause fin loss. Keep on the lookout for things in your tank that might be dangerous for your fish, such as equipment or decorations that are misplaced or broken or any other non-normal events or objects in your tank.

How To Cure Betta Fin Loss

Here are a few ways that you can hopefully heal up your betta’s torn-up fins!


The best way to cure fin loss, unfortunately, is to avoid it in the first place. To do this, make sure that there is nothing sharp or jagged in your tank for your betta to get caught on. This includes plastic plants (use real plants or silk plants instead), hard substrate, driftwood, decorations, and other sharp objects. 


Time is the best cure for all wounds, betta fish included. As long as you have an environment that is safe enough to not re-tear the fins of your betta, time will be the best cure for fin loss.

Slime Coat Booster

Fish have something called a “slime coat,” which is a sort of protective barrier of slime over their bodies. Using a slime coat booster can make the slime coats of your betta stronger, allowing them to heal while being more well-protected.

Anti-stress Additive

Although not a cure for the fin-loss itself, an anti-stress additive can be a great solution for helping avoid infection that can come from your betta swimming around with an open wound. 

Fix Water Conditions

Fixing the conditions of your water can be helpful in avoiding infection and lowering the stress levels of your betta that can cause it to be more aggressive (start more fights) or swim around too much too quickly. 

Get Better Tank Mates

If your betta’s fin loss is the result of fin nipping, you might need to consider getting better tank mates. It’s best to avoid angelfish, tetras, and other fish that are considered territorial or aggressive, as these are qualities that betta fish have as well. This means that these two types of fish will not get along, so it’s best to avoid having them in a tank together. 

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Q: What Does Fin Rot Look Like on a Betta Fish?

A: Fin rot usually shows up as blackened or bloody marks on the betta’s fins, starting on the tip and moving up as the infection spreads. 

Q: Is Fin Loss Normal for Betta Fish?

A: It isn’t normal for fin loss to occur, so it should be alarming. However, because of their fins’ long, flowy, delicate nature, it is not entirely uncommon for fins to become damaged in multiple ways. 

Q: Do Betta Fins Grow Back After Fin Rot?

A: Yes! Luckily, if the condition that caused it is handled, and, if severe enough, the infection is medicated, betta fish fins will eventually grow back after fin rot. 


Betta fin rot and fin loss are both issues that need to be handled as soon as possible if you notice them in your fish. Fin rot is an infection that can be treated by making sure your fish is in the right environment and also with medication. 

Fin loss is a physical injury that can be treated with a slime coat booster and by making sure the tank is a safe place for your betta to swim. 

Making sure your betta’s beautiful, flowing fins are healthy is one of the most important parts of being a good betta owner!

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