In a tank that size you might be able to get away with a pair of apistos in there. Can't really guarantee that though.
A couple of schools of different tetras, some nice plecs, and at least one pair of dwarf Crenicichla would look amazing in that tank, especially if it was planted.
A couple of schools of different tetras, some nice plecs, and at least one pair of dwarf Crenicichla would look amazing in that tank, especially if it was planted.