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Betta Fish Gill Flukes: Symptoms, Treatment & Prevention

Kristin Hitchcock

By Kristin Hitchcock

sick red betta fish

Betta fish are often advertised as being extremely hardy—but this isn’t always the case. They are prone to a variety of different illnesses and infections, including gill flukes.

Gill flukes are tiny parasites that attach to a betta’s skin. They prefer to live in your betta’s gills, where they breed. However, they can technically live anywhere on your fish.

Once infections get bad enough, they will often expand to other areas.

Without treatment, gill flukes can be deadly. They will cause wounds and sores, leading to secondary infections. Eventually, the gill flukes will infiltrate far enough into the gills to do severe damage and cause breathing problems.

Therefore, we recommend all betta fish owners learn about this condition to spot it and treat it quickly.

Causes of Gill Flukes

Healthy fish are typically better at fighting off infections than unhealthy fish. Therefore, the causes of gill flukes align with most other diseases.

Poor tank conditions are the primary cause of this problem. Too much ammonia and other chemicals in the water can limit the health of your fish, opening them up to diseases. All diseases are more prominent in dirty tanks. It is highly recommended that you veer on the side of caution when cleaning the tank, and clean it more often than not.

As parasites, these little bugs have to be introduced to your tank. Typically, this is done by introducing new plants and fish into the tank that are infected.

It is recommended that you quarantine anything before putting it into your tank. This period of isolation prevents gill flukes from being introduced to your established fish. Plus, if the new fish is infected, it is much better to treat them separately than dealing with a whole tank.

Gill Flukes Symptoms

Gill flukes are extremely small. You can’t see them. Plus, they spend most of their time hiding in the fish’s gills.

Instead, you’ll need to stay on the lookout for secondary symptoms like:

Gasping for Air

Gill flukes cause direct damage to your betta’s gills, which he needs to breathe. As the damage becomes more invasive, you may notice your fish gasping at the surface for air.

He may take more trips to the surface or barely leave the surface at all. (Though some betta fish are lazy and never leave the surface anyway!)

This symptom can be associated with a variety of things, though. For instance, ammonia poisoning is also linked to gasping for breath. Consider all of your fish’s symptoms when deciding on a diagnosis.

dumbo halfmoon betta
Image Credit: panpilai paipa, Shutterstock


Betta fish will try to fight the infection by coating their gills in mucus. Sometimes, this helps as it suffocates the gill flukes and makes it harder for them to get around.

However, it is often not enough, which means that fish keepers will need to step in and provide treatment.

The mucus is an obvious sign of this condition, though. Mucus rarely shows up in other infections but is relatively common in gill flukes. Gill flukes are the only condition that causes mucus on the gills alone.

Columnaris can also cause mucus, but it is usually throughout the whole body.


Gill flukes will make your betta quite itchy. In an attempt to remove the parasites, he may brush up against things in a wild manner. They may rub against the substrate, plants, or décor.

This symptom is common across most parasite conditions. Therefore, just because your fish is rubbing up against things doesn’t mean they have gill flukes. It could be a different parasite.

sick betta fish
Image Credit: yin8003211, Pixabay


Gill flukes often cause random wounds and ulcers to appear on your fish’s gills and body. Scraping can also cause this, though, so use your best judgment.

These wounds are a severe problem for fish, as they are prone to infections. Infections are even more common if the tank is dirty, which is often when gill flukes are around.

Damaged Gills

In some cases, you may be able to see the gills being damaged. They’ll look as if they have been eaten away—because they have.

In this severe case, your betta may not make a complete recovery. Once the gills are gone, it is difficult for a fish to survive.


Treating gill flukes is often not that difficult—as long as you do it early. There are many different treatments available, though some work better than others.

We recommend guaranteeing the fish and treating them separately. You don’t necessarily want to treat the whole tank, as it may damage your plants and healthy bacteria.

Here are several methods for treating gill flukes:

Anti-Fluke Medication

You can purchase medication specifically for treating flukes and other parasites from most major pet stores. You may have to special-order it online, as it is a bit of a niche product.

Follow the directions on the package of the medication you choose.

Generally, this method will involve treating the water and then waiting for a specified amount of time. Multiple dosages may be necessary.

sick betta in aquarium
Image Credit: Wirestock Creators, Shutterstock

Salt Bath

Gill flukes don’t like salt. Therefore, increasing the amount of salt your fish is exposed to can do an excellent job of killing them. This method isn’t as effective as medication, but it can be helpful for minor cases or those where medication is not readily available.

Performing a salt bath is pretty simple:

  1. Remove your betta from its tank.
  2. Add 30 grams of salt to a second tank full of only water.
  3. Put your betta in the salt tank. Watch for signs of distress. If your betta looks like he’s in trouble, add him back to the standard tank.
  4. Remove the betta after 4–5 minutes.
  5. Repeat for 3 days.


Preventing gill flukes is all about keeping your fish’s tank clean. If you stay on top of tank maintenance, then your betta should be able to resist new infections.

Of course, there are some other steps you can take as well.

betta fish swimming near the substrate in the aquarium
Image Credit: Andrej Jakubik, Shutterstock

Quarantine All New Fish and Plants

You should separate all new fish and plants from your new tank for at least 2 weeks. This time allows infections to become apparent, which you can then treat before adding the fish or plant to your tank.

Treating a single quarantined fish is much easier than dealing with an entire infected tank.

Assess Water Quality

Betta fish were not made to live in small bowls, despite some of the advertising from the major pet companies. Fish kept in bowls are more likely to get sick, as the water quality is typically lower. There is less room for the fish’s waste to spread out.

Keep your betta fish in an appropriately sized tank of at least 10 gallons. Perform regular water changes as well. If your tank is cycled, you will need to perform them less often. If it isn’t, you should perform at least a 25% water change every day. Don’t change all the water at once, as the change in water parameters will stress out your fish.

hand holding PH test
Image By: M-Production, Shutterstock

Provide Quality Food

Fish flakes are not appropriate for betta fish, as they are obligate carnivores. Instead, choose a floating pellet food that is made up of primarily other fish.

Check the ingredient list and choose one that includes fish as the first few ingredients. The type of fish doesn’t particularly matter. You want some fish.

You can also feed your betta a mix of life food. Bloodworms are often a good option and are widely available. You can find them frozen at most pet stores.

Healthy food can prevent infections by keeping your pet healthy. Unhealthy foods may keep your fish alive, but they won’t keep them in their top-notch health.

Reduce Stress

There are several ways your fish may feel stressed. Bettas are solitary animals. If you keep them with a bunch of other fish, they may feel stressed.

Improper water conditions, frequent handling, and other interactions can also cause problems for betta fish. Stress can contribute to infections, as it can severely damage your fish’s immune system.

fish divider


Gill flukes are a common parasite that attacks a betta’s gills, hence the name. They can cause severe damage to the gills, which can lead to death if left untreated. Your fish needs their gills to breathe, after all.

Poor water conditions and anything else that causes a drop in your fish’s immune system can lead to flukes. However, they typically must be introduced through an outside source, such as a new fish or plant.

There are several symptoms, though many of them are shared across a range of diseases. Many of these symptoms are centered around the gills, which can give you a pretty good indication it’s gill flukes.

You can treat gill flukes with medication and salt—though this latter option only works some of the time.

Featured Image Credit: Yasin Fadlilah, Shutterstock

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