A freshwater dip is the last resort that you should try, and only if the fish is having trouble breathing or other distress. The ich will fall off the fish but you are just putting it back in the tank which now has ich. A freshwater dip can also stress your fish to death so I wouldnt try it.
Get a small empty tank and put your fish in there and let the tank run fishless is the only way to actually 100% get rid of ich. The freshwater dip will only cause whats on the wrasse to fall off, thats it.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.