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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 times.
These are simple to use and are an essential piece of kit for any koi keeper.

To accurately detect any koi parasite causing an infestation of your koi, you will need to take a skin scrape. This involves using a microscope slide to carefully remove a small quantity of mucus from one of your koi. The mucus is then sandwiched between the slide and a cover slip and inspected through the microscope. We would recommend that upon purchasing your microscope, you ask your koi dealer to demonstrate this technique to you. This will help avoid causing any possible damage to your koi.

If you suspect you have a koi parasite problem, skin scrapes need only be taken from two or three koi, if parasites are found, it is safe to assume all koi are infested by the parasite and therefore the entire pond will require treatment.

Before any parasite treatment is used in your koi pond, it is vital that you know the exact volume of water and temperature, and that adequate filtration and aeration is provided. Parasite treatments will lower the dissolved oxygen levels in the pond so we recommend adding additional aeration when using any chemicals in your koi pond. You must also switch off any ultra violet sterilisers / clarifiers and ozone equipment.

See More Koi Parasites

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)
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... (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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