I think the main neon tetra problem is how mass produced they are. They breed thousands of them and keep them in a chemical soup to keep them alive, but when put in a normal healthy tank, they don't have that artificial immune system and just die. I've never kept neons, but I've had great luck with cardinals. Never lost a single one until the tank crashed after 2 years when I started to give up fish keeping.
I've never had luck with dwarf gouramis, but the only one I've kept in a really long time was given to me sick, so I don't think they count. I had good luck with blue rams until I let the tank go and it crashed, but when I have the money (next summer?) I really want to do another Amazon planted tank and rams are on the mental stock list
I've never had luck with dwarf gouramis, but the only one I've kept in a really long time was given to me sick, so I don't think they count. I had good luck with blue rams until I let the tank go and it crashed, but when I have the money (next summer?) I really want to do another Amazon planted tank and rams are on the mental stock list

they die in the first 24hrs.