1st off not a true amazonion biotope due to senegal bichir. but in terms of amazonion fish oscars are great and full of personality also there are some native eels that inhabit this area in the aqautic trade and i find they make great additions to setups were the show fish inhabits the top area of the aquariam, in my aro setup i had a pair of perruno cats they are great to watch although nippy at feeding time very attractice catfish with great barbells (would need the 3foot wide you mentioned though)