Attention to Stressors
Transporting Koi involves moving them from the source water at the point of origin to the water in the transport container. At the destination, the Koi are moved again, this time from the transport container to the quarantine facility and then to the final destination-pond. Stress and physiological stress-responses are caused by netting, handling and moving Koi, as well as by exposure to water changes. Whenever Koi are handled, the most important concept is to pay attention to stress. Stress harms the Koi by decreasing the effectiveness of its immune system. A less than perfect immune system increases the risk of infection or other health problems to the Koi being transported, and may increase the possibility of transmitting disease to other Koi already at the destination. Transferring fish from pond to pond is a common way to spread disease and parasites. Add to that equation stressed fish with suppressed immune systems that are highly susceptible to disease.
Koi are poikilothermic (cold-blooded) and that makes them different from the other animals we keep as pets, because their metabolism is tied to the temperature of their environment. In cool water temperatures, a Koi’s metabolism slows down and they appear to go dormant. When the Koi's metabolism is slowed, food takes longer to digest, and medicine takes longer to disperse and be circulated in their bodies.
Koi survive these long periods in cold water without nourishment because their reduced metabolism requires less food. Even when the water is warmer, Koi are not harmed by fasting for a few weeks. Before shipment, Koi can and should be fasted for a week so that all food clears their systems.
The fasting/holding period needs to be long enough for the food to clear the gut and for the fasting to have its effect on the metabolism, i.e. the amount of ammonia released into the blood stream is reduced. This takes a few days. A Koi’s metabolism increases with feeding and digestion, resulting in increased oxygen demand. Koi metabolism slows down during fasting, so fasted Koi will consume less oxygen during transport. Koi are evolutionarily adapted to intermittent feeding and the speed at which food clears the Koi’s gut is affected by water temperature and stress, and therefore it may take considerable time for fasting to produce a physiological effect.
Holding Tank Considerations
It is always critical to weigh the alternatives when handling Koi. If Koi are being transported to a Koi Show, a quarantine tank will be required for the returning Koi, and it is just as easy to set up the tank before the show and use it as a holding tank to fast the Koi. If the Koi are going on a one-way journey, it may be easier to leave the Koi in the pond and fast the pond, understanding that a total fast will not be achieved.
Optimally, Koi should be moved to a clean holding tank at least 1 week before transport. In the holding tank, Koi can be watched, fasted and allowed to recover from the stress of being captured and removed from the pond. The rest of the Koi in the pond may still continue to consume a regular diet. Temperature, pH and total alkalinity in the holding water should be kept stable.
Koi should have adequate water volume so that they do not experience stress from crowding and there should be sufficient aeration to reach oxygen saturation at the given water temperature.
Holding tank water changes should optimally be achieved by a slow, continuous trickle of fresh water rather than more stressful major water changes. The tank should have filtration that is suitable for a fish habitat of that water volume.
Attention to Slime Coat
The slime coat or cuticle is part of the epidermis layer of the Koi’s skin. It contains natural antibiotics and provides a barrier to parasites and bacteria. Netting and bagging Koi is bound to strip some slime coat. If there is a small gap in the slime coat and pathogens are present, Koi may become infected. While that infection is usually handled by the Koi’s immune system, if the immune system is weakened by stress, the probability of infection greatly increases If the slime coat is protected a Koi is much less likely to succumb to pathogens even if it is exposed when its immune system is challenged through stress.