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Fish eye flukes

Discussion about fish health and water chemistry.

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Post Wed Aug 08, 2018 3:53 pm
Passionfish Level 20 Member
Level 20 Member

Posts: 12030
Location: apple valley, mn
The eye fluke is a parasitic nematode that has a complicated life cycle that includes freshwater fish for a few fluke species. In addition to fish, the life cycle includes fish eating birds (gulls, loons, etc) and snails (Lymnea). Birds are not effected, birds consume infected fish and in bird gut the metacercaria become adult nematodes. The adult nematodes produce eggs via sexual reproduction, these eggs enter freshwater and hatch into miracidia. Miracidia are ciliated free swimming, infecting secondary host the snail. Asexual reproduction in snail results in release of millions of cercaria. Cercaria burrow into fish typically along lateral line often with bleeding. Bleeding may suggest false diagnosis of hemorrhagic disease. Cercaria may kill fish as they overwhelm organs and systems. However, cercaria life cycle is to become metacaria while in fish. Metacaria enter fish eyes and can be swimming in aqueous humor there. Metacaria are commonly called flukes, and a few fluke species are eye flukes. There are freshwater and marine species.

In a couple instances, fish farms have suffered massive losses from eye flukes. The parasite infestations vary in severity from year to year.

My interest in eye flukes occurred when the boy sent me a video of a fish in his tank. The video focused on fish eye and small "worms" swimming inside eye were easily visible. After reading about eye flukes a couple of facts became apparent; the only worm or fluke in eye are small number of freshwater nematodes, all nematode species share similar life cycles involving freshwater fish and fish eating birds, and cercaria may be on skin surface even as flukes appear in eye.

One web site suggested fish could be saved with medication. However, the consensus is fish will always have vision issues if saved. IMO, it is important to save healthy fish by killing parasites. In this case euthanizing fish with external cercaria in tank. Then killing all free swimming cercaria in tank. Formalin was used to treat one tank and Paraguard to treat another.

I believe the fish purchased from Florida source was raised outdoors or contaminated snails were brought into fish room.
Like a complete unknown

Post Wed Aug 08, 2018 4:03 pm
Passionfish Level 20 Member
Level 20 Member

Posts: 12030
Location: apple valley, mn
Image of eye fluke from web. Looking into posting video

https://goo.gl/images/oV3pDh
Like a complete unknown


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