Betta Inflamed Gills: Top Causes, Treatment, & Prevention

Inflamed gills in betta fish cause life-threatening breathing difficulties.

Fortunately, gill inflammation in bettas is easy to treat and prevent.

Knowing the symptoms of inflamed gills in your betta helps you identify the specific cause and mode of treatment.

So, what are the most common causes of inflamed gills in bettas?

A major cause of inflamed gills in betta fish is hyperplasia. Gill hyperplasia results from scarring due to a physical injury or bacterial infection. Other common causes of inflamed gills in betta fish are parasites, bacteria, and ammonia poisoning.

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Signs and Symptoms Of Inflamed Gills In Betta Fish

Recognizing the signs of gill inflammation is vital for your betta’s health.

Even though betta fish can breathe air through their labyrinth organ, they still need healthy gills to survive. Inflamed gills are a fatal condition without proper treatment.

Early detection of gill inflammation gives your betta the best chance for a fast recovery.

Observe your betta fish for signs and symptoms of inflamed gills, as listed below.

Extreme Redness

Fish gills use blood vessels to filter oxygen from the water into the blood. These blood vessels give healthy gills a light red color.

When a betta suffers from inflamed gills, the blood vessels dilate.

The inflamed gills turn dark red as more blood is brought closer to the skin’s surface.

Your betta’s gills appear as if they are almost bleeding on closer inspection.


Another notable sign of inflamed gills is obvious swelling.

Gills are sensitive organs, and they swell when they become injured or infected.

The swelling results from dilated blood vessels, which also causes redness. 

Gills Do Not Close Completely

As the gills swell, the gills flaps cannot close completely.

Open gill flaps prevent your betta from absorbing adequate oxygen into the bloodstream.

This condition is often confused with a betta flaring its gills.

When a betta flares its gills, the gill flaps can still close completely. During normal gill flaring, the gill flaps close again after one or two minutes.

If your betta cannot close its gill flaps, the gills are constantly flared and stick out from the body.

Rapid Breathing

Rapid breathing is a common symptom in bettas with inflamed gills. As you observe your betta fish, you will notice the gill flaps opening and closing more than usual.

Rapid breathing increases as the betta struggles to get oxygen through its swollen gills.

The constant opening and closing of the gill flaps are very tiring for the betta fish. Rapid breathing usually leads to death without prompt treatment.

Bettas Will Gasp For Air

When a betta cannot get oxygen through its gills, the fish uses its labyrinth organ to breathe.

A betta with inflamed gills spends more time near the water’s surface, gasping for air.

The labyrinth organ allows the betta to inhale oxygen from the atmosphere. But it is still not enough to ensure the fish gets adequate oxygen.

Excess Mucus on the Gills

There is usually a small amount of mucus on a betta’s gills. This thin film of mucus acts as a protective coating against bacteria.

When an infection or parasite is present, the mucus on the gills multiplies.

In a betta with inflamed gills, excess mucus forms on the gills, making it difficult for the fish to breathe.

Thick, sticky mucus is often a sign of an underlying infection.

Bumps or Growths

Healthy betta gills are smooth, but inflammation may cause bumps or growths to appear.

These bumps are an overgrowth of cells as the inflamed gills heal from an injury.

Bumps on a betta’s gills are usually a sign of gill hyperplasia.

Lower Activity Level

As inflammation in a betta’s gills increases, the fish becomes lethargic.

The struggle to breathe leaves the betta with little energy to move or eat.

If your betta is less active or not eating, this may indicate inflamed gills.

Treating Common Causes Of Inflamed Gills in Betta Fish

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Knowing the specific cause of inflamed gills in your betta allows you to use the correct mode of treatment.

The treatment for inflamed gills usually involves medication, tank cleaning, or a change in your betta’s diet.

Follow a strict treatment regimen to ensure your betta heals completely.

Gill Hyperplasia (Scarring)

Gill hyperplasia is a term for scarring on damaged fish gills.

Learn to recognize the following symptoms of gill hyperplasia:

  • Dark red gills
  • Gasping for oxygen
  • Gills do not close completely
  • Bumps/growths on the gills
  • Lethargy
  • Loss of appetite

When a betta’s gills become injured or infected, the skin cells grow to repair the affected area.

Sometimes, this overgrowth of cells causes bumps on the gills.


Gill hyperplasia may be permanent in severe cases. But, there are treatment methods to reduce the inflammation in the gills.

Treating the underlying cause of gill hyperplasia is crucial.

  • Causes of gill hyperplasia in betta fish include:
  • Protozoa/parasite infestation
  • Bacterial infection
  • Ammonia/nitrite toxicity
  • Poor water quality
  • Pantothenic acid deficiency

Start with a water change of no more than 25% of the tank water. Never change more than 25% of the water at one time, or you will disturb the tank’s water parameters.

This water change removes toxic levels of ammonia, nitrite, and other pollutants.

After the water change is complete, treat the tank with aquarium salt or a soothing water conditioner. Both of these treatments kill bacteria and promote healing.

Always follow the directions when applying a treatment to the tank water. Adding too much aquarium salt or water conditioner is harmful to your betta.

Add the water treatment until your betta heals to prevent infections.

Gill Flukes

Gill flukes are a parasite known as Dactylogyrus. These parasites enter a betta’s gills, causing inflammation.

It is sometimes possible to see the small parasites in your betta’s gills. Gill flukes only measure 0.3mm long and look like tiny white worms.

As the gill flukes multiply, the gills produce more mucus in an attempt to flush the gills out. This causes your betta to have rapid breathing and gasp for air.

Gill flukes and their eggs enter your betta fish tank through live plants or aquarium decorations from an infected tank.

A betta fish or other tank mates infected with gill flukes are another way your tank becomes contaminated.


You must treat gill flukes in your betta fish with an anti-parasite medication.

Aquarium salt is sometimes used in mild infestations of gill flukes but is not as effective.

Move your betta to a quarantine tank during treatment. Adding anti-parasite medication to the home tank may kill beneficial bacteria and live plants.

Do partial water changes to the home tank and clean the filter to remove gill flukes. Adding aquarium salt to the tank kills leftover parasites and their eggs.

Bacterial Gill Disease

Myxobacteria causes the type of gill inflammation associated with Bacterial Gill Disease.

With Bacterial Gill Disease, the betta’s gills are dark red and appear swollen. There may be white or gray spots on the gills as well.

In severe cases of Bacterial Gill Disease, the betta’s gills may fuse together.

If Bacterial Gill Disease is not treated in the early stages, it is often fatal for betta fish.


Bacterial Gill Disease is difficult to cure. There are commercial treatments available to target the specific bacteria causing the disease.

Use a separate quarantine tank for Bacterial Gill Disease treatment.

Treating the betta fish in a separate tank prevents destroying beneficial bacteria in the main tank.

Physical Injuries

Betta fish gills are sensitive organs prone to inflammation from physical injuries.

Physical injuries occur in bettas for a variety of reasons, including:

  • Irritation from accidental contact
  • Aggressive tank mates
  • Contact with tank decorations

The injured gills swell and become reddened.

Any time your betta injures its gills, prompt treatment is necessary to prevent further complications.

Gill hyperplasia and secondary infections are common with severe gill injuries.

It is crucial to check on minor injuries in your betta, but they usually heal independently.


Aquarium salt is the best treatment for gill injuries in betta fish.

The treatment improves gill function and replenishes the betta’s electrolytes for faster healing.

Never add more than the recommended aquarium salt to your betta’s tank.

Too much aquarium salt reduces oxygen in the water, causing your betta to gasp for air. Your betta will stop eating and may become dehydrated, leading to death.

Ammonia Poisoning

Ammonia poisoning is a common issue with first-time betta owners and usually occurs in new tanks.

Allowing your betta tank to complete a nitrogen cycle before adding your fish is vital for preventing ammonia toxicity.

In a proper nitrogen cycle, ammonia converts to nitrite, which is then turned into nitrate.

Fish waste and leftover food are major contributors to an ammonia spike in an aquarium.

Weekly water changes and regular tank cleanings are necessary for reducing ammonia.

Aside from inflamed gills, your betta will show other symptoms of ammonia poisoning, such as:

  • Dark red or bleeding gills
  • Red lines on the body and fins
  • Gasping for oxygen
  • Anal or eye inflammation
  • Loss of appetite
  • Lethargy


Frequent water changes and tank cleaning lowers the pH and removes ammonia buildup. In an emergency, you may perform a 50% water change.

Commercial ammonia detoxifiers neutralize excess ammonia as well.

Ammonia-removing filter media is also an efficient way to clear ammonia from the tank.

How To Prevent Inflamed Gills in Betta Fish

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Preventing inflamed gills in betta fish is easier than most treatment options.

Proper tank setup and maintenance are important in keeping your betta fish healthy.

Providing your betta with a safe, clean environment helps you avoid many common diseases in your fish.

Betta-Friendly Tank Decorations

There are many aquarium decorations on the market, but they are not all suitable for betta fish.

Bettas love to explore, but their delicate gills and flowing fins are prone to injuries.

Sharp objects in the tank are the most common cause of gill inflammation in bettas. Avoid rocks or other decorations with sharp or rough edges.

Examine any decorations before placing them in your betta tank. If there is doubt about whether they are safe for your betta, it is best to avoid them.

A good test is to run a small fish net along your tank decorations. If the net gets snagged, it is unsafe for your betta.

Live plants are always best for a betta tank. If you use fake plants, ensure the leaves are silk, not plastic.

Plastic plant leaves have sharp edges and will tear your betta’s gills or fins.

The placement of tank decorations is important as well.

Avoid placing any objects too close to the sides of the tank. It is not uncommon for a betta to get stuck or injure itself in tight spaces.

Many new betta fish owners make the mistake of placing terra cotta pots in the tank for hiding spots.

Terra cotta pots may seem like a good idea, but the drainage holes are rough and create a hazard for your betta.

Live plants, smooth coconut shells, and betta logs are much safer options for hiding places.

Check out this aquarium log on Amazon for an example.

If you are using decorations from another tank, be sure to sanitize them first. Cleaning the decorations ensures they are free from bacteria and parasites like gill flukes.

Maintain Optimal Water Parameters

Ammonia spikes, improper pH, and incorrect water temperatures are major causes of inflamed gills in betta fish.

Investing in a quality thermometer and a water testing kit helps you stay on top of these issues.

Ideal Water Parameters for a Betta Fish Tank Include the following:

  • Temperature: 78-80° degrees Fahrenheit (25.5-27° C)
  • pH: 6.5-7.5
  • Ammonia and Nitrite: 0 ppm
  • Nitrate: < 40 ppm
  • gH: 3-4 dGH (50-66.7 ppm)
  • kH: 3-5 dKH (53.6-89.4 ppm)
  • Minimum Tank Size: 5 Gallons

Consistency in water parameters is crucial. Sudden fluctuations in temperature or pH levels can cause severe illness in bettas.

Test the tank water at least once weekly to ensure the ammonia, nitrate, and pH levels are safe. If the levels are unsafe, a partial water change usually corrects the issue.

If you have had recent water parameter issues, you must test the water more frequently.

Commercial ammonia and pH neutralizers may be used in an emergency.

A low-flow filter also removes harmful bacteria and circulates your betta’s water. This prevents high concentrations of toxins.

Most aquarium heaters feature a digital thermostat. But we recommend using a separate thermometer to ensure tank temperatures are correct.

Improper temperatures cause a betta fish to become lethargic or stop eating. Low temperatures also weaken a betta’s immune system, making the fish prone to illness.

Keep the Tank Clean

As a betta fish owner, setting aside time for regular tank cleaning and water changes is crucial. Keeping the tank clean prevents gill inflammation and many other diseases in your betta.

Algae buildup is a common issue in betta tanks. While algae are not harmful to your fish, it is harmful to live plants in the tank, and it grows very quickly.

Reduce the amount of algae on the sides of your betta tank by scraping it off once per week. Magnetic scrapers are great for this because they stick to the side of your tank for easy use.

Algae-eating fish or snails do all the work for you and are excellent additions to larger tanks. We recommend having at least a 10-gallon tank if you want to add some algae-eating tank mates.

A partial water change every week is also crucial to maintaining a clean environment for your betta.

Avoid upsetting your tank’s water parameters by removing no more than 20% of the water at one time.

When performing a water change, use the gravel vacuum to remove algae and fish waste from the substrate and decorations.

Use a water conditioner to neutralize chlorine in the new water and ensure it is close to the same temperature as the water already in the tank.

A sudden temperature change may cause your betta to go into shock.

Remove uneaten food after your betta finishes eating to prevent ammonia spikes and bacteria.

Add Aeration

Bettas cannot swim in fast currents, so the filter in your tank must have a low flow.

Sometimes, the low-flow filter cannot circulate the water enough to provide adequate oxygen.

Consider adding an air stone or a bubbler to your betta tank to increase oxygen levels.

Increased oxygen levels improve water quality and promote the healing of gill inflammation.

Watch your fish after installing an air stone or bubbler to ensure it does not interfere with the betta’s ability to swim.

Check out this affordable and quiet air bubbler on Amazon if you don’t already have one.

Feed a Healthy Diet

Bettas need a protein-rich diet to grow and stay healthy. Proper nutrition helps maintain gill health and prevents inflammation.

Provide your betta with a varied diet of high-quality pellets and freeze-dried treats.

Look for foods with quality animal proteins as the first ingredient. Avoid pellets made with extra fillers, as they are hard for your betta to digest.

Read more about quality diet in our article covering the best food for bettas.

Never overfeed your betta, as it leads to bloating and swim bladder disease.

Your fish’s extra waste may also cause ammonia spikes, leading to gill inflammation.

Isolate New And Sick Fish

When adding snails, algae eaters, or other tank mates, you must quarantine them for at least two weeks.

This quarantine period ensures the new tank mates do not have any diseases or parasites they may pass on to your betta.

These diseases or parasites increase your betta’s risk of gill inflammation.

Do Not Expect the Worst if Your Betta’s Gills Are Inflamed

Inflamed gills in a betta fish may be life-threatening but are easy to treat.

Understand the symptoms and specific causes of gill inflammation so you may provide the best treatment.

Create a safe environment for your betta to avoid injuries associated with inflamed gills.

Maintain correct water parameters and establish a regular cleaning schedule. This prevents most causes of inflamed gills in your betta.

Learn more about the betta fish tank setup and maintenance process in our complete guide at the link.

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Toni Tedescucci is a freelance writer who loves all animals, especially betta fish. When she isn’t busy writing for Betta Fish Bay, she’s spending time with her family or getting cozy with her cats and a good book.

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