Is Ich CAUSED by bad water quality?
I, myself, believe that bad water quality cannot make ick (or ich) appear out of thin air (ahem, water). I've always read that if it appears even months after any induction of anything from another tank that may or may no be infected then it was already in your tank, introduced by something from an infected tank. The most likely thing that kept it from becoming visible to the owner's eye is probably good water quality and health of the fish.
However, everywhere I go I run into people insisting that this, much like a fungus or bacteria infection, can appear in a tank even without being introduced; literally out of thin "water" or "air". I don't believe this.
So, I thought I'd make this tread for anyone who wants to throw in their opinion, explore the dark mysteries of this parasite, and to share their opinion. It's open for anyone to use and to throw a link to or even to copy my words and use them (with a link to this thread, of course, so whoever you're explaining this to can read the whole thing) to their own heart's content.
What do you think of this great debate?