Thank you everyone for all your suggestions. I have now got 2 cardinal tetras remaining. Neither one has any spots that I can see. My plan now is to wait 2 weeks and then, if all seems well, move the threadfin rainbows to the tank. At that point , they will have been in the QT for 6 weeks.
It has been hard watching all these fish die, but I think I did all that I could. I have learned that cardinals are happier at temps that are equivalent to discus temps. Much as I wanted to have them in my tank, I am not sure that I will try them again. I would hate to go through this again. Once I get the threadfins in there, I may feel that that is enough, but I love a school swimming around in a large group. Most schooling fish are smaller than the cardinal tetras and I don' t want them to be food for the angels. Any suggestions.?
It has been hard watching all these fish die, but I think I did all that I could. I have learned that cardinals are happier at temps that are equivalent to discus temps. Much as I wanted to have them in my tank, I am not sure that I will try them again. I would hate to go through this again. Once I get the threadfins in there, I may feel that that is enough, but I love a school swimming around in a large group. Most schooling fish are smaller than the cardinal tetras and I don' t want them to be food for the angels. Any suggestions.?