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Columnaris (Cotton Wool Disease)

Columnaris (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 to ulcers and a thin appearance.

Often mistaken for a fungal infection because of its mold-like lesions, Columnaris is a common bacterial infection in cultured fish, particularly livebearing fish and catfish. Its name is derived from columnar shaped bacteria, which are present in virtually all pond environments.

The bacteria are most likely to infect fish that have been stressed by such conditions as poor water quality, inadequate diet, or handling and shipping. Columnaris can enter the fish through the gills, mouth, or via small wounds on the skin. The disease is highly contagious and may be spread through contaminated nets, specimen containers, and even food.

Treatment with anti-bacterial medicine is usually effective.

See More Koi Diseases

Anchor Worm (Lernaea)

Anchor Worm (Lernaea)

Lernaea (also spelled Lernea) is a genus of copepod crustaceans commonly called anchor worms, parasitic on freshwater fishes. They mate during the last free-swimming (copepodid) stage of development. After...(click on product image for more details)
Costia

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)
Dropsy (Pine-Cone Disease)

Dropsy (Pine-Cone Disease)

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)
Ergasilus (gill maggots)

Ergasilus (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.
Fin Rot and Ulcers

Fin Rot and Ulcers

A number of bacteria are associated with fin rot, lesions and internal hemorrhaging, notably Aeromonas and Pseudomonas. Ulcers usually start at the site of an injury, the bacteria then infect it causing...(click on product image for more details)
Fish Lice (Argulas)

Fish Lice (Argulas)

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)

Product Compatibility Chart

Every pond owner with fish, at some time or another, will probably have to medicate their pond. Though Koi are extremely hardy, it is very important to keep a watch on their environment to keep them at...(click on product 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...(click on product 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. Flukes are...(click on product 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...(click on product image for more details)