I had 7 neons tetra in my tank and am now down to 3. I noticed 2 yesterday who had white fungus on their mouth area, 1 was also very discoloured. I removed them both from my main tank, I am not sure if this is neon tetra disease? Two died and I had removed from the tank. I have 3 left who appear healthy and are acting normally, should I remove them from my tank or keep them in the main tank? My angelfish, zebra danio, glolight tetra and my bristlenose pleco are all fine, it just appears there was something wrong with my neons. Thanks for the help.