I think you're going to disappointed if you're looking for African non- shellies for a 29 gal. As was mentioned some of the West African species remain smaller ( kribs, jewels ). You could keep a juvie pair of calvus/ comps for quite some time but it wouldn't be a forever home. I know you're set on Africans but what's wrong with some of the other cichlids? Apistos, Rams, etc remain small and show interesting behaviors.