Dear Michael, thank you for openly speaking of your bad experiences. Most people like to speak about positive issues only, the disappointments are treated with silence. But for all other people it is very useful if one is bold enough to speak about those, too. Therefore congratulations to your openness.
I have only one wish: that you stay to your love of these small brilliant fish. It is easy to abandon a special interest after having made such a bad experience, but I want to encourage you not to do so and stay.
One could learn from it that all wild caught fish could be ill but one is simply unable to see it from the beginning. It might have been the same to me. Therefore, to take precautions is very unseful: generally put a small amount of 2-amino-5-nitrothiazol in a tank with newly adopted fish. Often, in the very beginning, it can stop the development of several diseases. The more early it is used, the more effective it can be.
Stay! Peter