depends on the fish you want, for example Mbuna you could do about 20-25, with 1m to 3f, and you get loads of beautiful colours and have a great mix of fish. with them u could have plecos, occasionally i hear about crayfish or a ray happily in there too. an aged (really quite old and peaceful) american cichlid sometimes works, but this is more rare and wont leave much space for your africans.
i suggest so many africans per 75 because overstocking reduces aggression, it just puts up the bioload. plus allows you to remove any 'nasty' fish and u still have lots of fish left.
look up on google at the colours! africans in general, but some haps are stunning. plus zebras, they are my fav.
most africans are very energetic and have their little squabbles and friends like a proper little socialite group! very interesting. i know angels do some of those things and are very graceful, but africans have the all out bang lol!