Okay, I have been reading through alot of posts and i have noticed that alot of people are content to say "I have tetras" or "tetras can be vicious/destructive" or things very much to that nature. This happens to be one of my pet peeves.
Tetras are a very large family of fish, covering Piranha, Blind Cave, Neon, Serpae, etc. These are all very different fish, all very different sizes, different food requirements, etc.
Tetra range in size from several feet to less than one inch (rumour has it there is a 9 foot tetra, the name escapes me at the moment, that is supposedly a man eater). A neon tetra is happy eating "hikari micro-pellets" the Piranha is happy eating the Neon. It would be kind of like the fish saying "i have primates" not terribly descipitve... is it a human, a chimp, or a gorilla?
Try to learn the names, please... esspecially when asking a question about compatiblity/disease... the specific kind of Tetra can make a world of difference.