Not many peeps know the ingredients of Interpet meds,
i would guess it does include copper which could harm/kill the snail, but i am not sure (actually i really dont know!!!)
Waterlifes Protozin DOES contain copper according to email they sent me ages ago, not sure on Interpet
KING BRITISH WS3 does NOT contain Copper and treats White Spot
You may have to sacrifice the snail (if the only med you got is the interpet), as White Spot should be treated as quickly as possible
Can you not remove the snail for a while?
Sorry, you said snailS, so more than one!!!!
I'd be suprised if anyone can say for sure if Interpet number 6 xcontains copper, that company are notorious for not revealing their ingredients