quick dip. does this really work

i don't think it does. if anything, it makes things worse by stressing fish even more. not only deeping the fish fast is not long enough for ick to even feel anything, ick often is so deep under the skin that it might not even going to feel longer periods of fresh water deep.

freshwater dips of 5-10 minutes will kill parasites. but i dont believe in them. This is because it stresses out a fish which makes them even more prone to disease. it is very likely that there is already some type of disease or parasite in your tank, and if you add a new fish to a new environment after it has been in a cool bag for 2 hours AND has jsut been in freshwater, it is goign to make it even more inviting to any disease. Plus not all parasites and diseases are external. there are many internal ones that would not be affected.
IMO, freshwater dips are in no way a substitute for QT.

it woul depend on the type . i believe some have alarval stage or at least some type of stage where they find a new host. i could bemistaken

yes, they could, but often don't. i noticed plenty of times that there is always a blue tang in my store who breakes out in ick, but nobody else ever does in the same tank.

FW diping only workd for parasites and does not work for bacterial or fungal diseases.

Rohn