tank mates for my aro are bottom dwellers, i have endlicheri endlicheri and endlicheri congicus together with my aro, for me the tank look balance because the aro stays up and mid tank while the bichirs stay at the bottom
My Aros share the tank with a Spotted Royal Pleco L330, and Leporacanthicus Joselimai L264, and a Reticulated Pimelodid. The R. Pimelodid cleans up any Beefheart the aros miss.
How about a couple of large severums?? I have heard of large discus been kept with arows, as long as the water quality is perfect. its all trial and error.