With active bichirs like a delhezi, sen and a polli it might be fun but I would add something that would be in the upper areas.If I did an all bichir tank how fun would that be?
Its tough with so many different fish you can keep yet only so many tanks you can have, lol. Been there myself. With this idea of a 75 gallon it limits you but you are on the right path by asking questions first.Would silver dollars work? What about Bala sharks, or maybe a cichlid that swims a lot at the top