That was 30 years ago. On a recent trip to a local LFS, I purchased a Pearly-Scale Butterfly fish. After being placed in my quarantine tank, I noticed it definitely has Ich. Fortunately, I’m a lot smarter now and the fish was promptly treated, released from quarantine, and has been doing fine in a community tank ever since.
Marine Ich has been running rampant in this hobby for at least 30 years, perhaps much longer. Surely in this amount of time the importers, the exporters, industry support groups, or even LFS’s would have gotten together and figured out how to wipe out this parasite from the supply chain. But they haven’t. It keeps propagating (and surviving) from the South Pacific holding tanks to your living room aquarium. There are procedures such as dips and medications that can stop Ich in its tracks. But this doesn’t look like it’s going to happen anytime soon. The ornamental marine business is a rag-tag industry of rogue fish collectors and corrupt, unregulated island-countries. When clownfish sell for $0.03 each at the dock, there isn’t much incentive to install treatment facilities. The bottom line is that it is your responsibility to deal with Ich on any fish you buy.
Do not think for one minute that a fish with clear fins in your LFS’s tank does not have Ich. The parasite normally attaches to the gills first, which cannot be seen. And not all fish scratch when infected with Ich. Many LFS’s use copper in some or all their fish holding tanks. This is an excellent measure to minimize the spread of the disease, but it does not necessarily prevent the parasite from coming home with you. First off, the copper concentration may have drifted below its therapeutic level. the knee at which copper kills the parasite is very slim. Secondly, it takes at least 7 days for attached cysts to dislodge. If the fish hasn’t been at the LFS very long, the copper won’t have enough time to work.
I don’t know what the odds are of buying a fish today infected with Ich, but talking with fellow aquarists across different parts of the country, the consensus seems to be approximately 2 out of every 3 fish either have Ich or a related life-threatening parasite (i.e. Oodinium) when purchased. Folks, this is an epidemic. If this was happening to humans, the world would be in deep shit. Such a statistic makes cancer and heart disease look like the common cold.