When do you need laboratory support?

Koi keepers should never jump to conclusions when their fish are off colour as, so often, it is an over reaction at the outset that makes a problem worse.

Water testing for ammonia, nitrite, pH, KH, chlorine and chloramine should be carried out before any action is taken. In addition, testing the level of dissolved oxygen is important as this supports both the Koi and the pond biology and is an overlooked parameter. In many ponds the water is never tested and yet optimum living conditions are vital for healthy Koi. Poor conditions can cause irritation, excess mucus, and lethargy in Koi and, as such, signs are observed with different health problems the pond water should be eliminated first so it is known to be safe.

If the pond water tests are all satisfactory and the fish are irritated, a parasitic infection could be the problem. It is safer to have mucus smears taken by a dealer or a pond consultant to identify which parasite is involved as treatments can differ with the parasite. If no parasite is identified, the irritant may be a pollutant in the water which cannot be identified by the normal tests that are carried out at the pond side. If this is suspected do not introduce any pond treatment product until the investigation is completed as chemicals and pollution do not mix.

If abrasions are seen on the skin of koi it is easy to assume these are due to an injury when it can also be the early signs of an infection. There is information on bacterial disease on the LFH website.

Common Causes

The common causes of a change in the behaviour or the appearance of Koi can usually be eliminated without laboratory intervention. LFH do not undertake pond visits, as our investigations require laboratory conditions and equipment. Anyone concerned about their koi can call in a dealer or a pond consultant or we can be contacted by telephone for advice.

If mortalities are occurring and both water quality and parasitic causes have been eliminated, an examination may be advisable. Whilst the more common minor health problems may be obvious at the pond side there are many others that can only be diagnosed in laboratory facilities.

No two ponds are chemically or biologically identical and therefore what corrects an issue in one pond can make matters far worse in another. This equally applies to health problems as it should not be assumed that sick koi must be suffering from the same disease based on similarities in their appearance and behaviour. For example, If Koi refuse food, become lethargic, and spend time near a source of oxygen, this only signifies the fish are unwell. However, such signs are frequently thought to indicate a specific disease or condition when in fact there are numerous reasons why koi adopt this behaviour.

Article kindly reproduced with the permission of Dr. Paula Reynolds, Lincolnshire Fish Health.