True indeed. While far less likely than it coming from infected fish, there is still a chance that the ich parasite cysts are on the rock or structure that the coral comes on, just like any other coral parasite. Some say dips work the same on ich, but from what I’ve read, they are immune in their cyst stage to even 30min freshwater baths. Only drying them out will completely kill them, which is of course impossible in this case without killing your livestock as well. In an ideal world we’d quarantine even corals, but I’m sure only the most extreme of us would go to such lengths hahaha. What you could do at the very least to lower the chances of ich entering your system through new corals/rock is place your coral/rock in a holding tank with water from your main display for a few hours after dipping them in a coral dip, with no fishes. Isn’t foolproof but might help a bit. Sent from Singapore Reef Club mobile app