Just wanted to be sure
I almost half hoped it was just something simple like not cleaning the tanks, and it's not just all the fish at Wal-mart is all. But that stinks still, I'm glad you were able to give him so much attention before his time though, I'm sure he greatly appreciated that!!
As far as Bleach, it actually doesn't kill all the bacteria like Rubbing Alcohol does. Alcohol is completely sterilizing and will kill more. You can use both in conjunction and get a much better clean and it would be much more sterile than if you used just Bleach. There was research done (I don't remember where I read it actually) but a woman tested just how much bleach killed and there was surprising amount of bacteria and other things that survived through a 24 hour soak! So I use both for good measure anyway but alcohol is my go to sterilizer since I can just put it in a spray bottle, spray it over the sink, rinse and let dry and done