Are nijsseni difficult to breed.

[gex18]

I have 5 apist nijsseni (2 male, 3 female) in a 60 x 30 x 24" 400 litre juwel tank with discus, cardinal tetras and zebra plecos. Had the apisto about 8 months now, and what to know are they difficult to breed (as i have bred apisto cacatuoides VERY easily), first they had shallow plantpots (pot saucers to be exact) but they never used them, have swapped these for coconut shells, but are ignoring these aswell, anyone had experience with them, or got tips for me? BTW the dominant male is MASSIVE (must be 3 - 4" long), is this normal, will post some pics soon, to see if i deff have males and females (how are they sexed?)!