I have a koi carp pond and have got what seems to be fresh water lice in it.
Yesterday we added 20 new carps and not long after we discovered that one of the carps that already were in the pond, that hadn’t behaved completely normal lately, had a fresh water lice. I’m quite sure that this lice was there from before the new koi arrived. 

Even though we haven’t seen any, I assume that there might be some eggs or lice in the pond that haven’t attached to any fish yet. 
 

the new carps have been there less then 24 hours. 
 

our plan now is to take out the new carps and put them in our lotus pond and take the old carps, and the gold fishes that also were in the pond, and isolate them in a big bucket.
Then drain the carp pond for water and let it dry out. Hopefully this will kill the eggs and lice that are left in the pond. 

 

the shop we bought the carps from said that we should just remove the carps that have lice and treat them with a medicine called “sites”. Im concerned that there already are more unattached lice in the pond that will attach to the new carps so I’m skeptical to only use her approach. 
 

anybody have any recommendations, ideas or comments to the actions that I’m about to perform? Are there any other way of solve this issue? 
 

regards Augustinius

Copper sulphate will kill these parasites, you need to Google

for dosage and length of time to a cure,good luck , I always

quarantine new Koi before adding to main pool. 

regards worgeordie

1 hour ago, worgeordie said:

Copper sulphate will kill these parasites, you need to Google

for dosage and length of time to a cure,good luck , I always

quarantine new Koi before adding to main pool. 

regards worgeordie

Have you tried this with success yourself? I’m skeptical to adding chemicals. Last time we had problem we added medicine with the dosage instructed by the shop and all but 2 fished died. And it’s one of the last one that is dying now and that we found lice on. So it seems like the “medicine” kills fished but not lice....

Chemicals are the only way to get rid of lice. There are commercial treatments available. 

2 hours ago, Augustinius said:

Have you tried this with success yourself? I’m skeptical to adding chemicals. Last time we had problem we added medicine with the dosage instructed by the shop and all but 2 fished died. And it’s one of the last one that is dying now and that we found lice on. So it seems like the “medicine” kills fished but not lice....

I have not used Copper in a Koi pool, but have used it in marine aquariums, a lot, never killed

the fish, but would kill all invertebrates inc crustaceans, fish lice are crustaceans, it did not kill

the marine fish, Koi are a lot tougher than marines,should not be a problem, you just need to

know how much water you have to calculate the dosage and length of time to kill them all and

their eggs, Google it, when using treatments it's always advisable to increase aeration.

regards worgeordie

.

Have you considered potassium permanganate.

7 hours ago, cleopatra2 said:

Have you considered potassium permanganate.

Yes. But after what I’ve been reading it’s good for killing lice but it don’t kill the eggs