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Skin and Gill Flukes

Skin and Gill Flukes

Gill and Skin flukes are two of the family of monogenetic trematode genera, all of which are characterised by the large grappling hooks which are used to attach themselves to their victims.

Affected Koi often exhibit classic signs of irritation and flash, jump or rub themselves against objects in the pond in an attempt to rid themselves of their attackers.
Flukes are not visible with the naked eye. When viewed under a microscope, the parasites are clearly visible as nearly transparent and worm like, and the hooks are clearly visible.

Gyrodactylus (skin fluke)

Gyrodactylus is one of two common worm type parasites which the koi keeper may encounter. The parasite is worm like in shape and it has hooks with which the parasite attaches itself to the koi.

This koi parasite reproduces live young. Being hermaphrodites, all of the adults are capable of producing young, and each one will carry a single larval parasite in its abdomen. Further more, this unborn parasite is also developing a larval parasite in its abdomen before they are even born, and in as little as one day after being born, those young can also give birth. So it’s easy to see that this koi parasite is very prolific, and one individual is capable of reproducing into thousands in a short period of time. When viewing this parasite under a microscope you can often see 3 or 4 developing parasites within each other.

Gyrodactylus (skin fluke) Video Clip 1 Gyrodactylus (skin fluke) Video Clip 2

Once this parasite is attached to a host koi, it lives and feeds on the mucus skin and blood of the koi. The parasite is capable of surviving without a host koi for five days.

This koi parasite can be treated using Kusuri Fluke M.

Dactylogyrus (gill fluke)

This koi parasite is very similar to Gyrodactylus in appearance. It has a set of hooks with which to attach itself to the host koi and these are surrounded by a number of smaller hooks.

The two parasites differ however in their method of reproduction, this koi parasite is an egg layer, and can lay up to two- dozen eggs per hour. Water temperature is important as the reproductive rate increases in warmer water, and decreases in colder water. The same applies to the time required for the eggs to hatch. In warmer water hatching can take only four days, whilst in colder water it may take as long as thirty days. This is a very important fact to remember when treating this koi parasite as most treatments will not kill the eggs, and they can hatch even after treatment and re-infect the fish. For this reason either the initial treatment has to stay active for at least four days, or you must do a second dose of the treatment.

To treat koi infested with this parasite you will need to use Kusuri Fluke M, take further skin scrapes to ensure all parasites have been eradicated.

Dactylogyrus Video Clip 1 Dactylogyrus Video Clip 2

See More Koi Parasites

Koi Parasites and Treatments

Koi Parasites and Treatments

Identification of Koi parasites. Most koi parasites are not visible to the naked eye. In order to correctly identify any koi parasites you will need a microscope with built in light and a magnification of 400... (click on image for more details)
White Spot (Ich)

White Spot (Ich)

Caused by Ichthyopthirius multifiliis. The white spots on the skin, gills and fins are individual protozoan cells that are under the skin and feed on the body fluids and cells. They then punch out of the skin and... (click on image for more details)
Trichodina

Trichodina

Trichodina is one of the easiest protozoan parasites to detect under the microscope as it is almost perfectly round with hundreds of hooks which resemble cilia found its periphery and it constantly rotates as it... (click on image for more details)
Costia

Costia

Ichthyobodo necator (Costia) This koi parasite is extreamly small (10-20 microns long) and a magnification of 100 times is the absolute minimum required to identify costia, 400 times is ideal. When taking a skin... (click on image for more details)
Chilodonella

Chilodonella

Chilodonella cyprini. Chilodonella is another protozoan parasite which effects the skin and gills of koi.This koi parasite is typically between 40 and 70 microns in length and is oval in shape. Again,... (click on image for more details)
Anchor Worm

Anchor Worm

Lernea (Anchor Worm). This koi parasite is most commonly found on newly imported koi, and should be dealt with by your koi dealer, it is rarely a problem for the koi hobbyist. It is visible to the naked eye and... (click on image for more details)
Fish Lice (Argulus)

Fish Lice (Argulus)

Argulus another crustacean parasite, round and up to 1cm wide. They have a sucker to hold on to the Koi with needle-like mouth parts which they stick into the Koi and inject a toxin. This causes intense... (click on image for more details)
Dropsy

Dropsy

Raised scales (rather like a pine cone) and eyes standing out from the head. Dropsy itself is not a disease, but rather a result of some other cause. Dropsy is a term given to the swelling that occurs... (click on image for more details)
Cotton Wool Disease

Cotton Wool Disease

Columnaris (Flexibacter columnaris) or Cotton Wool Disease is another bacterial infection. The common name comes from the white tufts that develop around the mouth and spread to the body and fins, often leading... (click on image for more details)
Finrot and Ulcers

Finrot and Ulcers

A number of bacteria are associated with finrot, lesions and internal hemorrhaging, notably Aeromonas and Pseudomonas. Ulcers usually start at the site of an injury, the bacteria then infect it causing further... (click on image for more details)
Gill Maggots

Gill Maggots

Gill maggots are the mature females of the parasitic crustacean Ergasilus. Ergasilus (gill maggots) will appear as grayish black and white parasites several millimeters long infesting the gills. Heavy... (click on image for more details)
Saprolegnia Fungus

Saprolegnia Fungus

One of the most common fungal infections of Koi. The fungal spores will grow anywhere on the Koi, including the gills, initially germinating on dead tissue. Their threadlike hyphae release digestive juices which... (click on image for more details)
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