gill flukesWHAT IS FLUKES?

Fluke is a parasite with two different types :-gill flukes and body flukes. Flukes do have external sucker with hooks that attaching to the host. They are one of the most common types of aquarium and pond parasites, but barely seen with the naked eye. Both type of flukes can be found in a goldfish simultaneously. Both of them reproduce differently, Gill flukes lay eggs, body flukes produce live young.

Flukes will not bite the fish or suck blood, but feeds on the fishes slime coat, therefore endanger the fishes protective layer and allow penetration of other parasites.




Flukes are normally introduced into an established tank with the transfer of new fishes from the pet store without the means of quarantine the new arrivals.

Transferring flukes into your tank can be prevented by  quarantining new fishes from pet store for at least 30 days , and ensure that any equipment used for more than one tank is sterilized before sharing it between tanks.



  • Clamped fins
  • Split fins
  • Less activity
  • Tend to eat less or not interested in food
  • A goldfish isolating itself from the others
  • A goldfish rubbing or scratching itself against tank furniture, which is known as “flashing”



If you suspect the presence of flukes in your tank. one of the best way to diagnose it is scrapping the gills and examine it under a microscope.

Eliminating flukes from the tank can be quite challenging. Most of the treatment involve toxic chemicals like formalin. Thus the control of the dosage is important. i would suggest Formalin (37½ % Formaldehyde in solution). Place the infested fish in a clean water with the formula of one teaspoon of non-iodized salt/gallon and 20 drops of formalin/gallon.  Spread evenly. Leave the fish for 10 – 12 minutes.At the first sign of stress, remove the fish into an isolated tank that has had one teaspoon of non-iodized salt per gallon added.

Repeat this treatment again after 1 day and probably another time on the second day if there is evidence there are still flukes present.  Sterilize the isolated tank 12 hours after treatments to flush away shed flukes.

It is extremely important when breeding goldfish that the eggs are flushed with clean water and put into a container with water that hasn’t been in contact with adults.
Gill flukes are particularly dangerous to young fry under a month old and can kill off an entire brood in two or three days. The fry appear to have white beards hanging beneath their gills and if you look carefully, they can be seen moving.


Advisable on a salt dip . Add 24 tablespoons of non-iodized salt/ gallon to a container. Dip the fry for 30 seconds and quickly place them into a isolated tank with 1 tablespoon of non-iodized salt / gallon. If the fry don’t appear too shocked, repeat in one hour.


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