I've never kept N. maranguensis myself (because I've never seen them for sale before!), but the general view seems to be that they are less aggressive than N. brichardi. That said, a tank with a 36 x 18" or a 48 x 12" footprint would work for a small group; 48 x 18" would be even better. I think the general consensus is that a 20L or a 29 would be the minimum for a well-bonded pair. Either way you will need lots of rock work and caves.What tank size would you need for some colony action? Always wanted a brichardi species tank.
I had a well-bonded pair of N. brichardi in a 29 many years ago and they raised abundant fry, which were very easy to sell. I would imagine that selling N. maranguensis fry would be even easier. All of the brichardi group make great species tanks, as the juveniles are so cute with their lyre tails, and of course the little ones look after their younger siblings. Very cool.