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A stressed pet may cause even more stress to its owner.

After all, your pets cannot express how they are feeling and what is bothering them. However, many pet owners, including fish keepers, develop strong bonds with their precious companions and can often tell if they are under stress.

At the same time, there are a few sure signs that indicate your Betta fish needs extra care and attention — and clamped fins are one of them. So, if your Betta has clamped fins in your aquarium, it is perhaps time to read this guide and find out what is bothering them.

What are Clamped Fins in Bettas?

Sick Betta with clamped fins
Photo: TrueArrabi

Often confused with fin rot, clamped fins in a Betta may be a symptom of underlying diseases or poor tank conditions. When this happens, the mesmerizing, fluttering fins that make a Betta fish so attractive clamp up and may curl towards its body. 

One aquarist puts it interestingly, pointing out how clamped fins may look like they have been dipped in oil and made to stick together. Furthermore, a fish with clamped fins may show other signs of stress, including lethargy, a change in color, lack of appetite, and the inability to swim straight. 

Why Does My Betta Have Clamped Fins?


Any aquarist knows that stress cuts short the lifespan of a fish. And although Betta fish are generally considered low-maintenance, they may get stressed out for a host of reasons, not limited to small tanks and incompatible tank mates. 

Poor Water Quality

Pristine waters and proper tank parameters are essential to ensure that your Betta fish lives a long and healthy life. Apart from a broken filtration system and inappropriate water temperatures, irregular water changes may result in poor water quality, which may leave the fish stressed. 

Parasitic Diseases

Betta fish, also known as the Siamese Fighting fish, are an aggressive species that pick fights with others — and sometimes themselves. Indeed, injuries from attacking their own fins or other tank mates may cause fins to get disfigured or curled. 

Or perhaps, a tank mate may have introduced a contagious parasitic ailment, which it passes on to the Betta. That said, clamped or curled fins may be a symptom of disease, including parasitic, bacterial, or fungal infections.

Genetics And Old Age

Generally, when Betta fish get older, their appearance deteriorates as they lose their sheen and their fins curl up. Considering how Betta fish have a life expectancy of about two to four years, it is normal for their fins to twist or fray around the ends as they approach this age. 

However, it is worth noting that some Betta fish may live up to ten years under the right conditions. 

Curled fins may also be a result of a genetic anomaly. And just as you cannot undo the wear of old age, Betta fish that are genetically predisposed to curled fins cannot be cured; nor can you reverse these genetic conditions. 

How To Treat Clamped Fins Betta?

Testing The Water Parameters

Maintaining suitable tank conditions and frequently testing the water may help avoid any instances of clamped or curled fins. 

For starters, consider how Bettas are freshwater fish native to Southeast Asia and thrive in warm temperatures. To replicate its natural surroundings, ensure that you place these fish in a freshwater tank with a pH that hovers between 6.5 and 7.5. Moreover, you need to maintain a stable temperature of 76 to 81 degrees F. 

Next, check that the concentration of nitrate remains under 40ppm. In addition to curled fins, high nitrate levels can cause deformities, such as bent spines and spastic swimming. Even more dangerous than nitrates are nitrites and ammonia, which should be removed and ideally kept at zero ppm. 

The best way to keep your Betta fish safe from these toxic compounds is by changing the water regularly and avoiding overfeeding. Additionally, you should introduce a biofilter to the tank and test the water weekly to ensure that these water parameters are at optimal levels. 

Calm Down A Stressed Betta Fish 

Betta fish are an aggressive species that will readily attack one of their own if kept in the same tank. At the same time, they are bad swimmers that cannot outrun their bullies. As a result, you may want to research extensively before introducing a new tankmate. 

Anyhow, Betta fish are unlikely to get lonely and may live by themselves — provided that they have enough space to swim around and explore. That said, you should ideally put a single fish in a five-gallon tank with plenty of room to swim and accessories to hide behind. 

Identify Potential Diseases And Treatments

The curled and clamped fins in bettas are not an illness. However, they can be a symptom of the following diseases. 


Black spots, discoloration, and rusty-looking spots around the gills and the belly may be symptoms of Velvet. This parasitic disease is often a result of improper water conditions that you can prevent by treating the tank with a water conditioner. 

Fortunately, remedies for this illness, such as Bettafix, are readily available on the market. 


Betta fish may develop white patches all over their body as a reaction to high levels of nitrite, nitrate, and ammonia in the water. This disease is known as Ich, or Ick, and should be treated with a salt bath or Fish-Zole.

Anchor Worms

As the name suggests, anchor worms are identifiable by stringy, white worms that stick to the fish’s body. Common antibiotics to treat this parasitic disease include Methylene Blue and Parasite Clear. 

Final Thoughts 

As they say, “prevention is better than cure,” — and this definitely holds water for a fish like Betta that is prone to curled fins when put under stressful situations.

In fact, many beginner fish owners have the misconception that Betta fish can live happily in small tanks. And so, they force the fish to live in closed, ammonia-filled dirty surroundings — which can stress out anyone, not just your fish.

That said, curled fins are not a problem by themselves. On the flipside, they may be a sign of an underlying problem that you have to find out with a little bit of empathy and a lot of research!

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Jeff Colt

Jeff Colt

Hello, I'm Jeff- an aquarium enthusiast with over 25 years of experience caring for a wide array of tropical fish, including koi, goldfish bettas, cichlids and more! For me: Aquariums are like jello - there's always room for more!

4 thoughts on “Clamped Fins in Bettas (Symptoms, Causes & Treatment)”

    • I wouldn’t recommend keep a betta fish in 2.5-3 gallons. It’s hard to keep the parameters consistent in 2.5 gallons without daily maintenance. Even the slightest change can cause a huge swing. The bigger the tank, the easier it is to maintain.

      • Sorry, just to clarify, 2.5 – 3 gallons is harder to keep the parameters consistent than a larger (5 gallon) tank? How does this make any sense? Would it not be harder to keep the parameters consistent in a larger tank?

        • Hi Chloë

          Smaller tanks have less water, which means that the ammonia has less room to disperse. As a result, smaller tanks tend to have higher levels of ammonia and higher pH levels. Additionally, water temperature fluctuation happens quickly in a small amount of water. So, if you want to keep your little guy happy and healthy, you will need to constantly monitor the water temperature and make sure it stays within the safe zone.

          While it is actually the opposite when it comes to large tanks. The temperature stability in large tanks is much higher due to the amount of water they contain. It will take longer before the water temperature or quality can affect the inhabitants. Thus, maintenance is way easier!


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