In this case, the mention is of a quarantine tank. For the vast majority of hobbyists, that is flat out unrealistic because of space and time and even money considerations. However if you have an over and under stand, I would urge you to set up a quarantine tank on the bottom. The equipment need be just a box filter, a thin layer of gravel and some plastic plants or a couple unraveled, soap-less, plastic pot scrubbers. (The gravel and glass could be imported from your regular tank. If the new box filter had been run in your established tank for a couple of weeks, you pretty much import your nitrogen cycle with you.)

I would suggest that a good submersible heater of at least 2 watts per gallon and a tight fitting glass top.

Over the course of the two-week stay, I would also suggest that aquarists treat the fish with an anti-parasite combination. I'll skip the long lecture on parasites and meds, but a very significant percentage of commercially available fishes are infected with something which may take up to 3 months to show itself. The two-week quarantine is useless for them. When the Camallanus or other worms are found, it may be too late to treat them.

Your male may indeed have had difficulties with tailrot before you brought it home. I have looked at a quarantine tank as a way to try and heal that fish.

However Bruce Hansen, an Australian physician often on the RML (Rainbowfish Mailing List) in the past and one of the most thoughtful hobbyists I've encountered, had a different take on quarantines. Primarily they were there so if the new fish was sick, it died there and didn't take out the sometimes very valuable contents of one's regular aquarium. He is not a cruel person and has been a good source of advice on dealing with diseases.

But he is realistically pointing out that by the time we know what the new malady is, with the new fish, it may even be too late for that fish. And if that animal is put into a community tank, the five dollar dead fish then took hundreds or thousands of dollars of fish and (more importantly) pets with it. Furthermore, a fish from a shop may have some immunity to a disease, but carried it up to a stressed member of the regular aquarium and, "Goodbye stressed member!"

Since the level of exposure and even non-lethal infections on commercial fish must be better than 10% of them for each of several diseases, one can see why the odds are so great that there will be a disaster when new ones are added to an aquarium.

"Oh, and I would never flush my fish. I was just frustrated." Ah! I think we all understand the feeling. I think Bill Cosby used to carry on about shooting his children in the face with a bazooka. "I brought you into this world. I can take you out!"

It is easy to get too strident and preachy about things like flushing fish. Thank you for your tolerance. :)

Hope to hear from you again on GL. :)