Diseases and treatment

Here you will find the most common koi diseases and cures for them.

A microscope is an essential tool in identifying parasites. As with all treatments there is a danger to the fish as well as the parasite. Using the wrong treatment or wrong dose could make things worse. If you are local and do not yet have a microscope and suspect an outbreak, I am happy to help with diagnosis. Bring along you sick fish or skin scrape.

IMPORTANT

PLEASE DO NOT BRING FISH, SCAPES OR WATER SAMPLES STRAIGHT INTO THE FISH HOUSE.

Chilodonella

Chilodonella is a protozoan parasite. It attacks the skin and gills of the fish. Severe infections can result in rapid fish losses and even the dicovery of one should be taken very seriously.Chilodonella cannot be seen by the naked eye and can only be diagnosed with the use of a microscope. The danger is compounded as this parasite can be active at all temperatures. Although a nasty parasite, treatment is quite straightforward. A good salt bath at the rate of 1oz per gallon can erradicte chilodonella as well as the use of Malachite green and Formalin.

Costia

This is a particularly dangerous external parasite which is active at a vast range of temperatures from 2 - 29 degrees. It can exist as a free swimming parasite or attached to a host. Diagnosis is by microscopic magnification of x100 to x400. Although they have a life span of just a few hours heavy infestations can result in high losses particularly in young fish.

Treatment is by way of Malachite green and Formalin.

Gill and skin flukes

There are two types of fluke which attack koi.

Gyrodactylus - skin fluke and Dactylogyrus - gill fluke. These are two most common types of worm infection encountered by the koi keeper. Identification is by way of a skin scrape and microscope. If indentified early, eradication is normally straightforward.

These parasites can be treated with a Flubendozole based medication. One treatment is normally all that is needed, but a further skin scrape should be taken after a few days to confirm.

Trichodina

This external parasite can only be seen with a microscope. At x100 they will appear as rapidly spinning discs. closer examination at x400 will show the hooks that Trichodina use to hang on to the koi. In large numbers it can damage the skin and can result in seondary infections.

Potassium permanganate is the recognised as the most reliable treatment for Trichodina.

There are, of course, more nasties. But these will be the most common you will likley come across. We are always happy to help with indentification and possible treatment of anything that is worrying you fish.

BORDER AQUATICS

HIGH GRADE JAPANESE KOI.