can black ghost knifefish go with small 3" discus?

i have wanted a black ghost fish for a while now and the fish shop i work at have finally got hold of some. then knifefish are only small at the moment but they'll soon grow. My tank has 3 3" discus in it and a couple of angels and all is well. I know a few ppl who hav kept discus and knifefish together but unsure of the size of their discus. I know knifefish love to eat neons and other lil fish but does anyone think my discus would be small enough to become lunch or even attacked?

(my tank has plenty of hiding places if that helps)

I have never kept discus with my albino ghost knife,
HOWEVER my angel fish & Ghostknife fight quite often & I have seen the ghostknife shock the angel fish, so much so that he hid for an entire day (when he is usually on the prowl)

I have been shocked by the little critter myself, not enough to hurt me but it made me jump (it feels like static electricity). I can imagine if ever the discus got in the ghostknife's way they would be treated in the same way & I don't think they'd handle it well.
Plus you have to remember they can grow up to 50cms long!
don't get me wrong, I can sit & watch her all day they are FACINATING, they can just be a little destructive and mines only 15cms long.

Mate i've kept a ghostknife fish with Discus for nearly a year. I did however sell him a few months back because he was soo big and i wanted to get some smaller fish.

If your knife fish is a juvi then i can't see you having any problems. He'll basically grow up with your discus and won't bother them.