So If we are talking about natural setup wouldnt a Tanganyikan tank be a perfect zebra tank rocks and peebles sort of a Goby tank, Eretmodus, Spathodus and Tanganyicodus Sp. strong waves just soft water just be sure that the decor is stable or else you end up with a few flat fish I know this so well it happend to me twice one with slate another one with a power head and you just dont kill one fish they squish them in groups st#pid fish they hudle in a group.
A thriving planted tank dont have to have sand you can plant them in pots or tie them on a drift wood and the best plant are the once that are floating anyways http://www.mobot.org/jwcross/duckweed/duckweed.htm
if you walk on the beach sand will swirl as you move along, it doesnt mean that they need the sand for courtship even sand building fish like Cyathopharynx Sp. or a little shell dwelling Neolamprologus multifaciatus will breed in a BB tank as long as you provide a place for them to deposit there eggs like a PVC pipe, in the past I used to use marbles to breed zebra danios it will help collect the eggs so the fish wont eat them.
wirajendi it really depends on what your intentions are for the fish, if it is only breeding them I highly recommend BB and when you have enough fry then you can do what ever you feel like it Like placing them in a 5 gallon bare bottom tank just like this one
A Bare Bottom 5 Gallon Eclipse in-between 2 black leather couches, the impeller of the power head broke and is now with out a power head and the pair still spawned

Female that just Spawned in a 5 gallon Bare Bottom tank even though it is bare this girl still looks good with a blue tinge on her when you view her on a good angle

eggs in the males cave in a 5 Gallon Bare Bottom tank

Good Luck