Please explain this one

[Reef Pilot]

Originally Posted by sully08

Quarentined him with about 30 lbs. of live rock, lots of flow and good filteration and did 10% water changes every week, always tested for ammonia and nitrites and there was never an issue

That's not good enough. If you did not QT with copper or do the hypo routine, you could still transfer ich to your DT.

I had this happen to me last year. I normally do the hypo routine, and have been 100% successful with that. However, last year, because I was also QTing some new inverts at the same time, I couldn't do the hypo, and just kept them all together in QT for 6 weeks.

The new fish looked fine, and there was no sign of ich, so I transferred them to my DT. About a month later, I noticed some ich in my DT (which had been clean for almost 2 years) and before long I had a full blown ich outbreak. It took me 2 more months of diligent feeding and frequent water changes before the ich ran its course and subsided. Unfortunately, I did lose 2 of my favorite fish, but all the rest survived OK. Ironically, none of the new fish got ich or showed symptoms, but they were obviously carriers. Maybe they were already immune to that strain of ich.

So just QTing fish for 6 weeks, without any treatment does not guarantee anything. My recommendation is hypo, though, not copper.