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Goldfish Flukes: Symptoms, Treatment & Prevention (Guide)

Nearly all goldfish sold at pet stores will have flukes. This is because the parasite will not manifest until the goldfish's immune system has been damaged by transit and the unfamiliar environment.

There are two basic forms of flukes: gill flukes, which are the most prevalent and are caused by the parasite Dactylogrus, and body flukes, which are caused by the parasite Gyrodactylus.

These parasites are trematodes, which are flatworms with external suckers and hooks for attaching to their host. These hooks transmit a lethal pathogen that forms sores on goldfish skin.

"Goldfish Flukes: Symptoms, Treatment & Prevention" by BestForPets (bestforpets.org) will instruct you on how to recognize, treat, and prevent goldfish flukes, which are prevalent among virtually all young goldfish.

Gill and Body Flukes Explanation

The flatworm parasites lay their eggs on the gill flukes, whereas the body flukes generate live offspring. Without a microscope, you will not be able to spot flukes, but a skin scrape will aid in the identification process.

Flukes are white and scarcely visible on light-colored goldfish, however they are obvious on dark-colored goldfish such as black moors. When it hatches, the worm is typically 1 millimeter long.

If not properly diagnosed and treated, flukes can become highly dangerous. Therefore, it is crucial to quarantine young fish and administer a broad-spectrum medicine to them. If one goldfish in the aquarium gets fluke, the others will also have it.

Symptoms of Gill Flukes

The following symptoms are caused by the first stage of the fluke parasite in goldfish:

  • Fish that rub their gills on any item in the tank or swim through the bottom.
  • Involuntary twitching during swimming
  • Concaved fins
  • Damaged gills
  • Having the appearance of yawning repeatedly
  • Rapid gill motions
  • Circumnavigating the tank
  • The act of striking the glass.
  • Scale loss or physical harm caused by rubbing against abrasive things.

Symptoms of Body Flukes

The second stage of flukes will exhibit the following symptoms:

  • Animated fins
  • Concaved fins
  • Scale trembling loss
  • Ulcers
  • Reddish areas
  • Black gill spotting
  • Wounds
  • Lethargy
  • loss of hunger
  • Weight reduction
  • Dull coloration

How Goldfish Get Flukes

Since flukes are so abundant in goldfish, you may wonder how these parasites are transmitted. Typically, an infected fish purchased is the source. This fish will transport the adult flukes, which will subsequently lay eggs in the gills of goldfish that appear to be healthy. Flukes thrive in goldfish farms and are resistant to simple treatments.

These goldfish end up in pet stores, where they infect one another and serve as hosts for the fluke eggs. Then, you acquire the goldfish and either place it in a brief quarantine or directly into the aquarium, where the flukes will feast on the unknowing goldfish.

In the later phases, the goldfish will begin to exhibit symptoms, and the appropriate treatment should be administered quickly.

The adult flukes are exceedingly difficult to eliminate and will typically remain on a goldfish with no symptoms.

Flukes on Goldfish Fry

If goldfish fry contract flukes, the disease is extremely lethal and can wipe out an entire brood within a few days. Adult goldfish with a fully developed immune system can deal with parasites more efficiently than juvenile goldfish.

The initial stage of gill flukes is sufficient to kill countless goldfish fry. The treatment of goldfish eggs and fry will differ from the treatment of juvenile or adult goldfish.

Treatment Options

Flukes are a difficult parasite to cure, as most aquatic treatments are incapable of killing every adult fluke. Fortunately, there are a number of effective therapies and aquatic drugs on the market for treating the symptoms of flukes and discouraging their egg-laying.

Treatment Sheet

1. Salt dips

Fill a tank or container for quarantine with dechlorinated water. Add a high concentration of aquarium salt, about 1 teaspoon per 1 gallon of water, and place the goldfish in the tank for 30 minutes every three hours during the day. You should continue for at least four days.

In addition, a half teaspoon of aquarium salt per 5 gallons can be added to the main tank. Although goldfish can tolerate low levels of aquarium salt, flukes cannot.

2. Medication

Flukes need a high-quality, broad-spectrum medicine formulated specifically for parasites in cold-water fish. These treatments are effective against flukes in all life stages of goldfish, from larvae to adults:

  • The Tetragoldmed (safe to add into the main tank)
  • Seachem Metropolitan Complex (safe to add into the main tank)
  • Tetra General Tonic Plus (safe to add into the main tank)
  • NT Labs Anti-parasite (safe to add into the main tank) 
  • Methylene blue 15-minute dips
  • 1 hour Seachem Cupramine plunge

During treatment, activated carbon, invertebrates, living plants, and readily discolored surfaces must be removed from the main tank. Remember to adhere to the dose instructions on the labels for safe and successful treatment.

It is recommended to mix one or two different brands of medicine into the water and to add an additional air stone to the tank in order to boost oxygen levels.

The duration of Methylene blue, aquarium salt, and Cupramine dips should be shorter than one hour, and they should not be performed in the primary aquarium.

Preventative Measures

Prevention is always preferable than treatment, therefore taking the required precautions to protect your fish from parasites is the best course of action. All preventative methods must be natural and long-term safe for the main tank.

The drugs must be designed to be harmless to invertebrates, plants, and nitrifying bacteria. Natural remedies will not cover the gills and impede oxygen absorption.

Here are a few precautions you can take to ensure that your goldfish are not susceptible to flukes:

  • Before introducing additional fish, plants, and invertebrates into the main tank, quarantine them for six weeks.
  • Bio-elite vitamin C and garlic shield should be added after each water change.
  • Use Organic Aqua Fish Care minerals every time you change the water.
  • Utilize Bio-elite stress relief drops to organically increase the slime coat of the goldfish and make it tough for parasites to attach.
  • Use 2% aquarium salt after every water change in the main tank.


Flukes in goldfish are frequent, but they may be treated with the correct treatment. As soon as you observe fluke symptoms, you should take urgent action. The sooner quickly a goldfish is diagnosed and treated, the more effective the therapy will be.

Always observe proper tank hygiene and do not exchange equipment across tanks unless you are using a strong disinfectant in between. Washing your hands with antibacterial soap will prevent the transmission of fish infections to other aquariums.

We hope “Goldfish Flukes: Symptoms, Treatment & Prevention” by BestForPets (bestforpets.org) has helped you successfully identify and treat your goldfish for flukes.

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Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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