The op mentioned that they used SafeStart, but then after a few weeks realized they never added an ammonia source. They can't use ammonia to cycle at this point because there is still a fish in there. If the fish doesn't make it we were headed in that direction. As for now, I'm trying to get some nitrifying bacteria in there and get a cycle started. That single fish isn't going to be a sufficient source of ammonia so I was going to suggest a couple more fish, careful acclimation, close monitoring/testing, and water changes. I'm still skeptical though because of the surface foaming as mentioned. I still wonder what killed their fish so quickly.
I agree, that link is an excellent source.