Yep, one of my discus would line it up when the pep was on the wall and just swim straight for it crashing into it, the poor thing used to do a swan dive to the bottom of the tank and it was all over red rover. I no longer keep any BN with my discus.
This tank wasn't really meant for breeding & the peps in there are meant to be a cleaning crew to keep algae on my expensive BTN background in check. It's just a shame that it's this group that have bred. Not surprising I guess, because I purposely put my bigger peps in that tank, even though I still think of them as young adults.
I don't think there were many fry to start with, at least I only ever saw about 5. Currently 3 are still seen daily. I am making sure to keep a piece of zucchini wedged on top of the highest piece of driftwood, where the discus cannot go. I can nearly always spot the fry on the zucchini, so I'm hoping they stay there, where they will be safe.