possible yes, in my experience in 3 plus years buying from quality marine, carolina aquatics and consistent sea, i have never seen ich on any fish i purchased from them. Although i still treat all incoming fish in copper, in order to sell them as quarantined fish but i also sell conditioned fish which have not seen copper in my tanks and get sold as is to people that either do their own qt or simply dont (cheaper than market price) and i have never had a single person to report back with ich or velvet. Flukes yes, worms yes but nothing major ever. That is an amazing average knowing i sell 30-50 fish each week.