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 damage, and fungal infection can also occur.
Such holes result in osmoregulatory problems, leading to damaged kidneys and death if not treated. It is worth adding a weak salt solution to the pond as well as anti bacterial remedy, a concentration of 3gm per litter will help to restore the osmotic balance and reduce strain on the kidneys (make sure that the salt is fully dissolved before you add it to the pond).
Finrot is easily noticeable, the fins and/or tail look chewed and are red at the edges. Secondary bacterial and fungal infections can develop.
Anchor Worm
Crustacean parasite, Lernaea - Anchor worm is a common parasite on our Koi which is clearly visible to the naked eye and can reach 10 to 12mm. The parasite burrows its head into the Koi's tissue, under...(click on product image for more details)
Costia
Costia is a minute Flagellate with 3-4 flagella. It affects both the skin and gills of Koi, and reproduces itself by binary fission. Infestations of this parasite can appear very rapidly indeed, and Koi...(click on product image for more details)
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...(click on product image for more details)
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 product image for more details)
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 product image for more details)
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...(click on product image for more details)
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...(click on product image for more details)
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. Flukes...(click on product image for more details)
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...(click on product image for more details)