I'm going to disagree about the Leopard Ctenopoma - I think a single one would do fine for years (they're very slow growers), if not forever, in a 29 gallon tank as the centerpiece fish. One with maybe 4 platys would make a nice tank - the platys have color and are active, and they help the ctenopoma come out more (they do best with dither fish and no other aggressive fish in the tank). The ctenopoma would eat any platy fry.
Leopard ctenopoma are not overly active fish - they're mainly lurking predators and don't need a huge tank because of their activity. If you keep up with good water changes and keep the nitrates low, the fish will not be stunted. If a pair of convicts can be housed in a 29 (the males also grow to 6"), why not the leopard ctenopoma? Comparing tank sizes, the 29 gallon is 5 times the length of a ctenopoma and the width is slightly more than double the fish's length. In comparison, a 10" cichlid in a 75 or 90 gallon tank has less space (only 4.8 times the length and less than 1/2 the width - both tanks are 48.5" long and only 18.5" wide).
I guess where I'm going here, and I frequently see advice about fish size in relation to tank size, is that many of the fish that people say need a huge tank is based upon the need for territorial space not because a smaller tank will lead to a stunted fish. Some fish, while not large, are active swimmers and need larger tanks because of that. Some fish are highly aggressive and need larger tanks for that reason. Some fish truly are too big for a certain sized tank. However, other fish are less active, not aggressive, and despite being slightly larger will do fine in a 29 gallon tank...and I think a single leopard bushfish is just such a fish.
PS - lots of plants...I prefer real plants, but fake will work as well. Leopard bushfish like hiding places and can virtually disappear when they want to in a planted tank. However, as the only big fish with no other aggressive fish, I find mine to be as friendly as an oscar. When I added even kribs, the bushfish went into hiding mode that lasted 2 weeks after the aggressive fish were sold to the LFS.
Eric