Symptoms and Solutions For Gill Flukes In Fish

Last Updated on 2023-08-08

Dactylogyrus, or gill flukes, are a widespread parasite of fish. Similarly to common aquarium fish, these are classified into live bearers and egg-layers. They are parasites that can be found on the gills or skin of fish, and while even a few of them are usually harmless, an infestation can have a devastating effect on an otherwise healthy fish population.

Due to their minuscule size, flukes are typically responsible for injuries that result in subsequent bacterial infections. The gills aren’t the only place a fluke can connect to a fish; sometimes, it can go lower. This is typically owing to the presence of another infection in the same body system, and the resulting damage will be greater than if the parasite had attached itself elsewhere on the fish.

Find out what causes gill flukes, what symptoms it may cause, and how you may treat or prevent them.

What Are Gill Flukes?

Fish flatworms, or gill flukes, are parasitic worms. Freshwater fish are susceptible to a parasitic flatworm known as Monopisthocotylea monogenea. Many fish, such as catfish, goldfish, and cichlids, are hosts for these parasites because they attach to the skin, gill chambers, and mouthparts of these fish.

As adults, gill flukes are hermaphroditic, meaning they possess both male and female reproductive structures. Adult gill flukes are capable of laying anywhere from four to ten eggs each day, which hatch into either live or nonliving larvae. This free-swimming water movement is made possible by cilia, and the hatchlings have less than 8 hours to find a suitable host. The time it takes for a creature to develop from a larva to an adult is greatly affected by the temperature of the water it lives in.

What Causes Gill Flukes In Fish?

It is essential to have a thorough understanding of the elements that contribute to the spread of illness in order to successfully avoid and manage its occurrence. The question, then is, what causes gill flukes?

Water Quality Issues

Gill flukes, like most fish parasites, are typically found in aquariums and fish tanks with subpar water quality. Fish in ponds are also susceptible to parasites because their natural habitats are outside.This infection is more common in areas with poor water quality because the flukes there may grow and proliferate more quickly.

The flukes have a better chance of survival in low-quality water settings, which allows them to multiply more quickly within their hosts and transmit the infection.

The Presence of an Intermediate Host

Gill flukes can also live in other animals besides fish. They can also use fish and freshwater snails as intermediate hosts for reproduction. These hosts make it possible for the monogenean parasites to develop eggs in their bodies, increasing the parasites’ reproductive rate relative to solely feeding on fish.

Monogenean flukes pose a special threat due to the presence of these secondary hosts. Even though these secondary hosts provide food for some parasites, they can also be preyed upon by other parasites, which could increase the likelihood of infection in your fish.

Unhygienic Ways of Feeding

An additional common factor in fish contracting gill flukes is the giving of unclean food to the fish. If you leave flakes or pellets in water for too long, they might become infested with germs and fungi, which can then spread throughout your pet’s body. Feeding your fish flake or pellet food puts them at risk for gill fluke because the food can support the life of other parasites.


The number of fish in an aquarium, as well as whether the flukes are egg layers or livebearers, will affect the severity of the infestation. Within live-bearing fish, the fluke life cycle is far more rapid, making it easy to spread among a dense school of fish.

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What Are The Symptoms Of Gill Flukes

Understanding the symptoms of a fish infected with gill fluke is crucial. You may stop an infestation before it gets out of hand if you know how to spot the warning symptoms. Some major red flags are as follows.

Redness or Spots Around the Gills

Spots or redness close to the gills are the most obvious sign of this parasite illness. Blood-sucking flukes are to blame for this condition. These areas of skin will be noticeably redder than the rest of your body, and they may also have a slight purplish color. Skin fluke spots may look like pimples, but they are not the same as ich or white spot disease.

Overproduction of Mucus

As the condition worsens, secondary infections in the respiratory tract might cause an increase in mucus production. This is because the gills have been damaged by the flukes, causing an increase in mucus secretion. Depending on how much mucus has grown up around your fish’s mouth and body, it will seem yellow or white.

In extreme cases of infection, you may see your pet swimming with its head pointing downward due to the weight of the mucus.

Lack of Energy and Appetite Loss

Other signs that your pet may have this parasitic infection are drowsiness and a loss of appetite, even if there is plenty of food for them to eat. They may be unable to feed because the gill flukes have damaged their gills, or they may not be eating because they are sick.

Breathing Problems

Some fish might have trouble breathing. As a result of breathing difficulties, the body receives less oxygen. When fish detect oxygen at the surface, they will swim upward to take a breath. A lack of oxygen causes illness in fish.

Abnormal Behavior

Swelling of the skin is a stress symptom for fish, just like it is for humans. The fish’s unusual behavior shows that it is having trouble swimming underwater. The length of the parasite in the skin will grow as it contracts. The fish’s ability to swim will deteriorate gradually. Fish get sick when they experience pain and become unable to swim.

Tank Wall Scratching

If your fish is constantly wiping its gills and face against the tank glass, it may have gill flukes. There’s a chance this is because your fish is trying to get rid of a parasite that’s irritating its gills.

How Do You Get Rid Of Gill Flukes In Your Fish Tank?

Taking precautions to prevent your fish from contracting gill flukes is preferable to treating an already-infected fish. If you want to keep this from happening to your fish, consider the following measures:

Give Cooler Water Temperatures

Maintaining a water temperature of 50 to 68 degrees Fahrenheit is detrimental to the survival and reproduction of gill flukes in an aquarium or pond. Keep a reliable aquarium thermometer handy, so you can monitor any temperature shifts in the aquarium. Adding ice cubes to a tank without a heater can help maintain a more comfortable temperature inside.

It’s Important to Replace the Water Often

Maintaining optimal water conditions in a fish tank or pond requires constant attention. You must regularly change the water in the aquarium to keep the conditions optimal for your fish. One way to prevent parasite outbreaks is to change the water frequently. This will give the parasites less time to spread and multiply.

Contain and Quarantine Recent Additions

Quarantining new additions to the fish tank or pond is another effective method for preventing the spread of gill flukes. In order to prevent the spread of disease, new aquatic pets should be isolated in a quarantine tank for a few weeks before being introduced to their permanent tank mates. If you check your new fish for diseases and parasites right away, you can stop them from spreading to the other fish in your tank.

Supply Delicious, Healthy Food

Feeding your fish only high-quality pellets or flakes is the final line of defense against gull flukes invading your tank and eating your fish.

Upkeep of the Tank

A significant water change or thorough cleaning of the aquarium is strongly recommended if you believe your fish to be clear of flukes but are concerned that parasite eggs may still be present. The entire tank’s water is replaced during these maintenance periods, not simply the top 20%. Also, the gravel and the tank itself may need to be cleaned.

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How To Prevent Gill Flukes In Fish

Gill flukes can infest your fish tank or pond no matter how careful you are. There are a few options for getting rid of them in a way that won’t hurt your fish too much if this happens:

Prepare a Holding Tank

Isolating your sick fish is the first step in stopping the spread of disease. Untreated gill flukes in other fish in the tank will lead to reinfection, so it’s important to treat all of the fish in the tank. Quarantine is also the best course of action for dealing with other aquatic pets like snails and plants. Fish aren’t the only ones susceptible to gill flukes; in fact, many other animals and plants can get sick from them as well, such as shrimp, crayfish, and even some amphibians.

Know the State of Your Fish

Examine the gills for signs of gill flukes and then determine how bad the infestation is. Depending on the species of monogenean parasite, a freshwater dip may be sufficient treatment, while other parasites may necessitate professional medical attention from a vet or pet store employee. Taking a sample of the contaminated water to a vet, pet store, or fish expert is your best bet for getting an accurate diagnosis. Knowing what kind of gill flukes your fish has and how to treat them is essential.

Treating Gill Flukes

Depending on the severity of your fish’s case, you can choose from a number of different treatments for gill flukes. You can safely and effectively treat your fish with a freshwater dip if it only has a few parasites.

Will Gill Flukes Kill Your Fish?

There’s a chance that this illness will kill your fish. Infected aquatic pets will begin to show signs of distress if you do not act quickly to treat the infection. They could get sluggish or even stop eating as a result of this. However, this only becomes fatal if the fish in concern has a compromised immune system or was under extreme stress before the incident.

Columnaris Vs. Gill Flukes

Gill Flukes

Fish with flukes may exhibit behaviors such as rubbing against hard surfaces, moving their gills rapidly, secreting mucus all over their body, having their gills and fins eaten away, and developing red skin.

Flukes are flatworms that are just around a millimeter in length, and there are many different kinds. They behave similarly to ich in that they infest skin and gills, but the distinction is seen with a hand lens. Unlike ich, you should notice movement and maybe even eye spots. When left untreated, gill flukes will ruin the fish’s gills and kill them. Fish with drooping fins, fast breathing rates, reflections off tank decorations, and/or deflated bellies are all signs of a severe infestation.

The recommended dosage of potassium permanganate for treatment is 10 mg per liter, which should be soaked in for 10–30 minutes. Or you could treat the entire tank with 2 milligrams per liter, which would be a lot of work and would turn the water a weird color.

Fungus of the Mouth (Columnaris)

White spots on the mouth, chin, and mouth area, as well as on the edges of scales and fins, and cottony patches around the mouth are the symptoms. Clear, stringy stools, loss of appetite, and accelerated gilling may accompany gill infection. Its appearance mimics that of a fungal infection of the mouth, hence the name “Mouth Fungus.” Freshwater aquarium fish, especially live-bearing fish and catfish, are susceptible to this bacterial illness.

Columnaris causes an internal or external infection and can enter the fish by its gills, mouth, or small sores on the skin. It might spread slowly over several days or months, or it can spread rapidly as a result of lesions, wiping out entire fish populations in a matter of hours. Extremely contagious, it can be spread via infected nets, specimen containers, and even food. Water with an unstable pH, together with stress, injuries, insufficient food, and other environmental factors, are to blame for this illness.

Maintain your water with proper biological filtration and weekly water changes that involve vacuuming the substrate to prevent Columnaris. It’s important to keep the aquarium well-aerated, provide the fish with a variety of diets, and not overcrowd the tank. Columnaris can be cured with a gram-negative antibiotic. Columnaris disease is caused by gram-negative bacteria, but there are gram-positive bacteria that can cause similar symptoms. If you’re not sure, some aquarium experts advise employing both the positive and negative strains.


Are Gill Flukes Contagious

Infectious gill flukes can easily jump from one fish to another due to their direct life cycle. Parasite populations can explode in recirculating systems when fish are stocked at very high numbers.

Does Aquarium Salt Treat Gill Flukes

When dealing with cases of gill flukes that are not as severe, a salt bath in an aquarium can be an efficient treatment option. On the other hand, if the situation is particularly dire, you will be required to take medication.

Can Humans Get Gill Flukes

Any time your fingers come into touch with the gills or other bodily fluids of a sick fish, you run the risk of contracting one of these parasites. Symptoms of these parasites in humans can be similar to the flu, including high body temperature, weakness, and aches and pains. If you notice any gill flukes on your fish, you should probably keep your hands off of them.

 Can You See Flukes On Your Fish’s Skin

Due to their microscopic size, gill flukes are frequently overlooked while being the root cause of the harm that ultimately results in secondary bacterial infections. Given their minuscule size, you may only detect their presence by observing unusual behavior in your fish.

Melafix For Gill Flukes

As an all-natural antibacterial treatment, MELAFIX fish cure is effective against a wide variety of bacterial diseases in fish. Bacterial infections typically manifest themselves in the form of open wounds and abrasions, tail rot, eye fog, and mouth fungus.

Does Kordon Copper-Aid Get Rid Of Gill Flukes

Itch, velvet, anchor works, flukes, and other external parasites are all treatable with Kordon Copper, which is an effective treatment.

Does Levamisole Kill Gill Flukes

Levamisole is a typical anti-worm agent that is used to eliminate most worms that are found in fish. Levamisole is an excellent treatment for endemic internal parasites that can be efficiently treated. They can be found almost anywhere.

Can Gill Flukes Be Dormant In A Fishless Tank

In 20°C (summer) water, gill fluke eggs hatch in 4 days; in 1-3°C water, it takes 5-6 months (winter). Flukes that infect fish in winter deposit eggs remain dormant, and hatch in spring. Even if flukes die, their eggs will spread when water temperatures rise.


Unfortunately, gill flukes are a common problem among fish, but if treated promptly, they can be easily eliminated. Naturally, the most effective method is to stop them from infecting your fish in the first place; hence, you should be sure to adhere to our preventative recommendations in order to keep your fish healthy.

If you suspect your pet has gill flukes, it is imperative that you get a water sample, have it examined by a professional, and start treatment right once. If you catch the disease early enough, you can save the fish.

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