Osmotic shock will kill ick, this is why hyposalinity works, velvet, OTOH
, is a tougher cookie and IMO
is best treated with copper when possible.
dips are too stressful on the fish, the fish is already traumatized and we throw it in a bucket of FW
for 20 min (this is supposed to be the appropriate length for a FW
dip) and expect it to thrive in our SW
tank....just doesn't seem right. With proper quarantine, you will have the same effect on ick in the display, but the mortality rate will be lower from stressed induced death, IMO