| Renee, don't use copper!!!!! It is very dangerous for koi especially in cooler water of unknown softness/hardness. You need to take a breath and collect some facts before proceeding.
Koi normally can cope with a low level of ich presence. But weak koi can not. And no matter how many drugs are used, the ich will not go away on very weak koi. The weak koi actually excellerates the breeding process for ich.
Ich is very easy to kill. Salt, mal green, formalin, PP will all kill stages of ich. You need to pick just one. Do not keep using different ones as they are having the effect of weaking the fish and in some cases, the environment and biofilters.
Make sure you really have the ich parasite by using a microscope to ID them. Ich also like to be additional company when other parasites are present ( that initially weakened the koi and allow the ich to establish) so make sure you are not treating for ich alone if there are other non-susceptible parasties also on the fish).
Ich does not go away all at once. The compounds kill stages of the parasite until eventually there are no breeding age adults and you break the cycle. Heat helps in this regard by inceasing the metabolism of the parasites and shorting the stages of development. So you wear them down this way. But if you can't get the heat higher, then be patient and let the treatments knock off the stages as they become vulnerable. This could take 10-15 days.
I would do a good 25% water change with chlorine free treated water, and then I would add salt ( make sure you really know the gallonage of your pond and are not underdosing as this can be a common error when treating parsites) at the rate of 30 pounds per 1000 gallons. I would let this settle in for 24 hours and then add a standard over the counter malachite green and formalin solution at the manufacture's suggested rate ( typically 100 ml per 1000 gallons).
Do not feed the fish during this treatment and try and add extra aeration. If the pond temps are below 60 F the eradication can take a while. Above 70 F and they will be gone in 10 days. If the water is cool, you might want to do a second 25-30 %water change in 7 days and repeat the treatment only this time without adding any more salt. Best of Luck, JR |