I love Zoe as well. I soak all of my foods in it. (I alternate soaking my foods in Zoe, Zoecon, and Vitamin C). Like Bang, I love the Zoe and have been skeptical of garlic usage in the past. However, the more and more I use it and hear about using it, the more it grows on me. Some have recommended to use it with each feeding, but I don't agree with that method. However, when any of my hardy fish come down with ich, the garlic works within a day or two to rid them of the ich (both in freshwater and saltwater). I would much rather use the garlic than treat the fish or quarantine it in a separate tank because that is just even more stress on the fish.
On a similiar note, the same situation happened to me a few months ago that happened to your powder blue. My hardy engineer goby came down with ich after I moved some of my rockwork around, and after noticing this, I soaked my food in garlic before I fed him and the ich fell off of him within that day and since then he has been totally fine and ich-free.