Louis: We keep the fish in a flow through system with airtsones, with PVC pipe parts for shelter, the tank is low lit. We keep them there for three weeks and make sure they are eating. Standard treatment consists of three treatments (one treatment every third day) of 37% formalin (1 mL per gallon) for 45 minutes with the water turned off. Once the three treatments are done the fish are moved to another q-tank just in case any cysts of ich are still in the tank. If there appears to be any skin damage or infection, then we will first treat with nitrofurazone every night for a week or so, then start the formalin treatments. If you use formalin on a fish with open wounds or sores, it will be very irritating and can kill them.
If the fish come from areas where we know that monogenetic trematodes are a problem (e.g. Marshall Islands) we will give them a freshwater bath as soon as we get them and we usually repeat this before adding them to any display after they have gone through treatment.
We never use copper when Q'ing a fish, formalin works best for us.
Aloha!
JCD