First sign of NTD I would kill the infected fish.
There is a good chance that your other neons may be infected, especially if they came from the same store tank as the infected neon. Cardinal tetras are initially more tender than neons, but they are immune to NTD.
There is a good chance that your other neons may be infected, especially if they came from the same store tank as the infected neon. Cardinal tetras are initially more tender than neons, but they are immune to NTD.