I recently read an article online about having a west african biotope aquarium. He focused on the Congo River and his 190 litre had 6 african red eye tetras, 6 congo tetras, some upside-down catfish and a leopard bush fish.
There isn't much info about african red-eye tetras but they seem to be in at my lfs so I will have a go at those. And congo tetras are also in my lfs. Upside down catfish look interesting and leopard bush fish are not available at my lfs which is a pity.
So all in all
6 african red eye tetras
6 congo tetras
2 jewels
3 cuckoo catfish
Is that alright?