NEON TETRA DISEASE! 10points?

i think my shoal of neon tetras has NTD they are not shaoling all together as they normally would, often spuring out in 2's or 3's or alone, some are hanging around the filter, and 1 has already died, i have noticed white spots all over the neons and they have lost most or all of their red stripe and some of the blue part aswell, i dont have a seperate heated tank but i could keep the seemingly afectd ones in a floating cube? please help, give ideas for cures of what to do with the affected ones, if you dont think the symptoms i have posted are NTD please tell me what and what to do, i have a 56ltr cube aquarium with platies,peppered corydoras,amino shrimp,guppies and i am planning to add cloud minnows and flag fish, pleese help, tell me if the other fish can catch it cos i dont want a aquarium wide epidemic!!!! HHEELLPPP!