Fish carry ich. Gills are the primary spot.
inverts, anemone, and all do not....
BUT....
If you have something that has sucked in the ich, and it gets in your tank and exhails, then it will be in your tank.
Hense the QT and all for EVERYTHING.
Even if it is for a day or so for the non fish... Get it washed off and out of it's system some. Not like you have to leave it there for a month.