Had tropical fish for a while in the 70s. Enjoyed them, but they'd die unexpectedly. Plenty of the usual - neon tetras, guppies, black mollies, platys, catfish. I had one black Angelfish that lived long and healthy and grew quite large - but he died too
I used to get a lot of finrot, especially on the guppies' tails, and couldn't seem to get rid of it. Discovered children were easier to keep healthy, so gave up on the tropical fish.