I didn't see anything on the gill paltes-but I been burning up Google and I think I found something for treating it in ponds. I can get these products (ProForm C, Quick Cure) at place about 20 miles from my house and I'm headed up there on my lunch break.
This is from ponddoc.com. Great resource
You have to buy a product that stays active in the water for at least 2 weeks, bcasue of the parasite's life cycle-before reaching adult, the larvae develop in a cyst that's impervious to any outside influence. They can only be killed in the free-swimming stage - this is also when they're on the fishies, and vulnerable. Both these products stay active for that long-but if you need to retreat, you have to do a 25% water change so that you don't get an overdose of the med in the water.
http://www.ponddoc.com/koihospital/Diagnostic/Parasitic/Ich.htmTreating Ich
Treating for ich is the easy part! Yes salt will kill ich but it has to be in a strong enough dose. 3 lbs. of non-iodized salt per 100 gallons (yes, that's the amount!) will kill ich. The salt must stay in the water for at least 2 weeks so that it will kill any baby ich as well. We have a very pure salt that we use on our own guys that is wonderful to use for treating ich.
Salt in that high of a dose will kill or retard the growth of many water plants so often a salt treatment is more trouble than it's worth. For planted water gardens and koi or goldfish ponds that have plants we suggest you use either ProForm C or QuickCure. If your water temperature is not very warm you should use the ProForm C. You can use Quick Cure in spring or summer but not when the water is cold. Quick Cure is part of our Parasite Pak that addresses flukes, fish lice and anchor worm as well as ich and other parasites that salt will kill.
You may need to change most of or a portion of the water when treating for parasites. Make sure to have de-chlorinator on hand.
Emergency Procedures
Perform a salt treatment or treat with ProForm C or QuickCure.
What to Expect Next
Once ich is eradicated from your pond you should not have any residual affect from either the ich or the treatment except maybe that the fish have been stressed so that they are susceptible to anything that may come along. Just be "gentle" with the fish for a while and keep an eye out for ulcers or other problems that arise when fish are stressed.