African Biotopes (save for cichlid tanks) often get "ignored." But then African fishes are not as available and plentiful at your local fish store. African Barbs and Tetras can be downright hard to find. And Cichlids that aren't "assorted africans" aka assorted mbuna, may take some tracking down.
I was recently thinking (dreaming) of doing a big African riverine tank with lots of Anubias
and other plants, Congos Tetras, Nannaethiops unitaeniatus and some Synodontis cats. . . then I thought "how about some Gnathonemus Petersii, too? And before I knew it, the dream tank became an unrealizeable monstrosity!
But a pair of Kribs would fit. Don't know how amenable to close neighbors they would be in such a tank. My guess is the tank would be pretty much all about the kribs and some biotopically correct plants. Other modest sized african cichlids are the gorgeous but cranky Jewel Cichlid
, the interesting "blockhead" cichlids (Steatocranus Casuarius) and "Tadpole Cichlids" (Teleogramma Brichardi). Or maybe some shell-dwelling Tanganyikans (Lamprologus Brevis, L. Ocellatus), since they are small.
Or possibly look into killifish species. I can imagine an open-topped tank with suspended lighting above, half-filled with water and planted thick with miniature papyrus that grow out the top. Little annual killies swim around the submerged papyrus stems.
I know. It's wacky. The reason I haven't done it: my cats would eat the papyrus and then they'd jump in the tank.
I don't like to recommend any schooling fish for tanks much under 55 because of the need to keep them in groups sizeable enough to encourage natural behavior (as far as that's possible in captivity). And truly I am having difficulty imagining an entire "Biotope" from any continent in a tank of this size.
Tht's it. I'm tapped out. Now I will shut up and look for genius ideas to emerge from the great people on this forum!