Attention !! Related here is a very brief explanation only. Please check on the technical book for the details of diseases and their treatments.
Introduction - Koi Fish Diseases -
It is said that the optimal water temperature to keep Koi healthy is 24 ~ 25℃.
While, the water temperature that Koi-related bacteria is active and easy to proliferate is also 24 ~ 25℃. It is considered that various kinds of bacteria are living within the range of that water temperature in each season.
Parasites or bacteria are found in any pond water and in any fish, usually coexisting in peace with Koi harmlessly so far as the water is in good conditions.
However, Koi if under gone stress in an inferior environment, reduces its resistance to disease, bringing about an infection with parasites or bacteria outbreak under the bad conditions.
Detachment of scales due to bad handlings of Koi or any wound caused by collision against protrusions may sometimes result in an infection disease that develops by adherence of bacteria on the wound site.
Check Points to Detect Koi Fish Diseases
Watch fishes in whole, at the same time check each fish well on the following points.
If possible, check a fish body one by one everyday in detail to find abnormal in incipient stage.
How is water turbidity related to fish complexion?
Lightly greenish water with water-bloom is favorable to Koi health. But, cloudy water of higher turbidity will disturb appreciation or observation of Koi.
Such grayish, brownish or muddy water is not suited for Koi keeping.
Likely causes may be found in deficient capacity of settling in the tanks or filtration in the tanks, sludge accumulation, shortage of new water, shortage of dissolved oxygen, overcrowding, too much feeding and etc.
Examine water quality carefully (pH, ammonium, nitrite contents etc. )
How is grouping ?
Koi, separate from group into the corner or the bottom of a pond, floating near the water surface, or gathering around the pouring pipe(inlet) or drain outlet, are all in bad shape.
Could be a bacterial cause disease.
Is there any Koi with strange swimming ?
There must be something abnormal with a Koi, that rubs against the wall or the bottom of a pond, flaps up frequently on the surface, collides against the wall, trembles all over or swims crazily.
Have a good appetite ?
Observe whole groups of Koi to check if there is any not coming for feeding.
Also, check if there is any food left uneaten.
Decline of water temperature, lack of oxygen, increase of ammonium or Nitrous acid level, parasites or bacteria origin infection, or visceral disease could be causes of KHV.
How is Koi's dropping ?
Examine Koi's dropping if it is floating on water, or abnormal in color, or transparent or not.
Dropping, of a few millimeter in length, which sinks in no time to melt in water is normal.
Floating dropping, continuous dropping or gelatinous dropping are not normal.
How is body appearance?
Keep careful watch on such symptoms as congested fin or abdomen, abnormal in color, tumor, ulcer, abnormal cloudy body surface, skinny, swell, bend, eyeball pop-up, sunken eyeball, fin's tear or melt, external wound, parasites, abnormal breath, presence or absence of scale- rise and its state, attachment, protrusions, and swell of gill cover etc.
When gill cover is opened sometimes change in color is detectable.
Check it very carefully.
Koi Keeping Outdoors
An outdoor garden pond is the ultimate setting for fully appreciating the beauty and elegance of Nishikigoi.
The optimum environment for koi is a recirculating system that has good filtration, both mechanical and biological.
Outdoor ponds can be counstructed with concrete, fiberglass or even vinyl sheeting.
With the development and availability of efficient ready-made filtration systems, it is possible to enjoy koi keeping in any setting, from traditional Japanese style gardens to modern ponds designed strictly for raising koi.
Koi Keeping in an Aquarium
Like tropical fish, Nishikigoi may be kept in the house.
Then, you can be close to them and by viewing them from the side, can appreciate a new charm in Nishikigoi.
Small-sized Koi are particularity suited for keeping in the house, and if they become too big they can be kept outdoor.
Koi keeping on a Veranda
Nishikigoi may also be kept on verandas.
The space is much larger than that available in the house and the Koi can grow much bigger.
The aquarium is equipped with a filter so even if you have no garden, it is possible to keep Koi as if you are keeping them in a pool.