For smaller fishes, dont put those that'll make you cry if the aro eats em. Along with that thought, don't use any decors in ur tank so as to avoid hurting ur aro if he decides to take a shot at the smaller fish.
i got a 3in jardini, two 4.5in kois, a 4in pleco, a 1in red tail shark..
one of my koi punks around the jardini but he cant do much to him so i careless
but soon... >
Most bottom dwellers are nice tankmates for a silver. Stingrays, catfishes, plecos, loaches... As long as they are not bite-sized. Non-aggressive cichlids, fei fengs, dats... Lotsa suitable tankmates around.