Why can't angels and discus live together?

[Mettle]

I've heard from people that angels shouldn't be put in with discus due to some type of parasite that is transmitted from the former to the latter. I've also read that because of certain reasons that escape me - perhaps being captive born? - this is an issue of old and not so much of a worry, if one at all, anymore.

What's the relevance to this? And can anyone direct me to an article on it?

[Julie]

Hi Mettle, it's capillaria.  My friend keeps angels and discus in a 70 some gallon tank.  She's got them breeding at each end of the tank - not her goal though.  
I think mainly the school of thought here is why put a 10$ contender with a 50$ contender in the same tank.
They'll compete for food, they both can be nasty especially when spawning; and both susceptible to the same diseases.    Personally I think it might be a recipe for disaster, because the discus will likely suffer.
It can be done though, just qt properly.  And add a neon or two for effect.  :wink:

Julie