I bought two young BN's from Animates, not for breeding but in hope of a cleaner tank. One sprouted Bristles, the other didn't. There was alot a chasing and a bit of aggression but suddenly, the male stayed under his log. A few days later, little fry appeared. I caught 15 when they lost their yolk sacks but only 8 survived. I moved the pair into a 54 Litre when their tank needed deconstruction and a few days later they spawned again! I saw many eggs but can only count 5 fry.
In my opinion, based on my experince with these fish, as long as there are enough spawing sites and hiding spots, they shall spawn.