We are down to one fish. We believe the fish we got at PetSmart had something wrong with them. This is not uncommon for minnows, as they are used as feeders, and stores consequently do not properly care for them. The ones we got from Walmart were healthier. However, we seem to have an issue that looks like a swim bladder infection. Caught from the diseased fish? Just happens? No way to know. I have removed the little guy from the tank to his own little bowl, but he doesn't look good. The healthy one, and the snail, are looking OK. We'll see.
Update to the update: I may have spoken too soon. Our little guy in the holding bowl is looking better, and swimming better. Hmmm.
Update to the update of the update: Nope. We lost him. The other fish looks really good today, so keep your fins crossed.