African arowana, African species of puffers like the guys said, synodontis catfish, giraffe catfish, Bichirs as long as their not lower jaw species do to the fact they grow very large, so senegals and ornates, killie fish as long as you provide enough floating plants so that they can hid if the africans decide to get hungry, not to many things you can put to be honest, but from what i've given you. If you were to put a tank with all of these species of fish and get in to work, you would be one of the first that i've seen do a full on multi species african tank.