FYI, you're taking a chance not just on that fish, but every fish you have in your tank and every fish you're ever going to put in the tank.
Fine if you want to do it, but I wouldnt come here and start a thread basically stating how perfect this is, when it's the exact opposite thing an experienced fish keeper would do and certainly now what you want to convince new people to the hobby to do.
If the fish had any disease, every fish in your tank for now and years to come will be exposed to it. It could have ich, at a easily non diagnosed level, but flare up huge when stress comes on for some reason, a stuck heater, power outage, you name it. Every other fish contracted it as well and all the sudden you have 4-5 fish with massive ich outbreaks and going down quickly. Or flukes...
It's just not a good idea. And it's really not good to come post it as a positive example.