These parasites are worms that are most often seen on butterfly fish, angelfish, and wrasses. Usually, only one or two fish are infected but it can spread to all the fish in a short time. Common names include gill flukes and skin flukes.

They will appear as tiny worms, but can be very difficult to see on the fish. They usually attack the gills of the fish but also will attack the eyes too. You can usually see them by using a magnifying glass or when giving a fresh water dip, as they'll fall off the fish once the fish is dipped in fresh water. Gill Flukes are contagious and should be treated immediately, before they spread to the other fish. Gill Fluke eggs are resistant to medications, but the larvae and adults are susceptible. Unlike other parasites fish can cope with Gill Fluke infection for quite some time, especially large one, before they die from them.


Some symptoms include the following:
• Fish scratches but eats and does not display spots like with Ich
• Increased respiration rate
• Flashing and mad tank long dashes
• Open gill covers
• Weight loss in advanced stages
• Scratching the gill plate
• Difficult respiration in advanced stages with fish hanging near the surface
• Focal reddening where a parasite has attached
• Excess mucus production
• Hiding
• Secondary bacterial infections associated with severe infection

Treatments:
Prazipro is an very effect treatment in killing the Gill Flukes. General it take 2 treatment to get rid of the Gill Flukes, as the first treatment kills the Gill Flukes on the fish and in the tank, but not the eggs, which is why a second treatment is needed. In general it takes two weeks of treatment to rid the fish, and tank, of Gill Flukes. During the two week treatment you may not see the fish get better, as it will still be scratching, breathing hard, making long dash and hiding, until the two weeks are just about up, and then the fish will all of a sudden be fine and acting normal. Because of this you need to stay with the treatment for the full two week, even though you may not see any result right away.

De-Los is a product that also works very well but it's very hard on fish, and care needs to be given when treating with it.

Formalin bath will help eliminate the Gill Flukes but it takes quite a number of treatment, as the eggs and free float Gill Flukes will still remain in the tank and re-infect the fish over again.

Fresh water dip will work on the fish but you need to be careful, as with heavily infected fish removing all the flukes at once can leave holes on the fish, which could cause it to bleed to death.

Copper doesn't usually work and neither does Hypo.