Welcome to the aro fever marius!
In many peoples opinion, best aro tank is :
red aro (celestial dragon)
prochilodus (charming phoenix)
Datnoid (divine tiger)
Sexfaciatus (majestic shelter)
-sexfaciatus has never worked for me, I replace it with endlicheri endlicheri - earth dragon
really tho its up to you what you like and what works in your tank..
some people like rays with their aro, or big clown loaches or even clown knife..
some ppl love the gars with aro, some ppl like weird amazon fish I can't name off the top of my head but nonetheless, there is no right or wrong..
If you like a species, know it grows big.. Just ask, we can tell you if its compatible or not..